Sunday, March 31, 2013
Basics of Schmitt Trigger Circuits – Part 2
A Schmitt trigger is a simple concept, but it was not invented until 1934, while an American scientist by the name of Otto H. Schmittwas still a graduate student. He was not an electrical engineer, as his studies were focused on biological engineering and biophysics.
He came up with the idea of a Schmitt trigger as he was trying to engineer a device that would replicate the mechanism of neural impulse propagation in squid nerves. His thesis describes a “thermionic trigger” that allows an analog signal to be converted to a digital signal, which is either full on or off (‘1’ or ‘0’).
He came up with the idea of a Schmitt trigger as he was trying to engineer a device that would replicate the mechanism of neural impulse propagation in squid nerves. His thesis describes a “thermionic trigger” that allows an analog signal to be converted to a digital signal, which is either full on or off (‘1’ or ‘0’).
Little did he know that major electronics companies like Microsoft, Texas Instruments, and NXP Semiconductors could not exist as they are today without this unique invention. The Schmitt trigger turned out to be such an important invention that it is used in the input mechanisms of virtually every digital electronic device on the market.
The concept of a Schmitt trigger is based around the idea of positive feedback, and the fact that any active circuit or device can be made to act like a Schmitt trigger by applying the positive feedback such that the loop gain is greater than one. The output voltage of the active device is attenuated by a determined amount and applied as positive feedback to the input, which effectively adds the input signal to the attenuated output voltage.
This creates a hysteresis action with upper and lower input voltage threshold values. Most of the standard buffers, inverters, and comparators use only one threshold value. The output changes state as soon as the input waveform crosses this threshold in either direction. A noisy input signal or a signal with a slow waveform would appear on the output as a series of noise pulses. A Schmitt trigger cleans this is up - after the output changes state as its input crosses a threshold, the threshold itself also changes, so now the input voltage has to move farther in the opposite direction to change state again. Noise or interference on the input would not appear on the output unless its amplitude happens to be greater than the difference between the two threshold values. Any analog signal, such a sinusoidal waveforms or audio signals, can be translated into a series of ON-OFF pulses with fast, clean edge transitions.
There are three methods of implementing the positive feedback to form a Schmitt trigger circuit. In the first configuration, the feedback is added directly to the input voltage, so the voltage has to shift by a greater amount in the opposite direction to cause another change in output. This is commonly known as parallel positive feedback. In the second configuration, the feedback is subtracted from the threshold voltage, which has the same effect as adding feedback to the input voltage. This forms a series positive feedback circuit, and is sometimes called a dynamic threshold circuit. A resistor-divider network usually sets the threshold voltage, which is part of the input stage. The first two circuits can easily be implemented via use of a single op amp or two transistors along with a few resistors. The third technique is a little more complex, and is different in that it doesn’t have any feedback to any part of the input stage. This method uses two separate comparators for the two threshold limit values and a flip-flop as a 1 bit memory element. There is no positive feedback applied to the comparators, as they are contained within the memory element. Each of these three methods is explained in more detail in my next article.
Portable 9v Headphone Amplifier
High Quality One-IC unit, Low current consumption
After several requests by correspondents, the decision of designing a 9V powered Headphone Amplifier was finally taken. The main requirement was to power the circuit by means of a common, PP3 (transistor radio) alkaline battery. So, implementing a low current drawing circuit was absolutely necessary, though preserving a High Quality performance.
Portable 9v Headphone Amplifier Circuit Diagram
P1 = 22K
R1 = 18K
R2 = 68K
R3 = 68K
R4 = 68K
R5 = 18K
R6 = 68K
C1 = 4.7uF-25v
C2 = 4.7uF-25v
C3 = 22pF
C4 = 220uF-25v
C5 = 220uF-25v
C6 = 4.7uF-25v
C7 = 22pF
C8 = 220uF-25v
J1 = 3.5mm Stereo Jack
B1 = 9V Alkaline Battery
IC1 = NE5532-34
SW1 = SPST Toggle Switch
The appearance of the 5534 low-noise op-amp at a reasonable price was much appreciated by audio designers. It is now difficult or impossible to design a discrete stage that has the performance of the 5534 without quite unacceptable complexity. 5534 op-amps are now available from several sources, in a conventional 8-pin d.i.l. format. This version is internally compensated for gains of three or more, but requires a small external capacitor (5-15pF) for unity-gain stability. The 5532 is a very convenient package of two 5534s in one 8-pin device with internal unity-gain compensation, as there are no spare pins.
The 5534/2 is a low-distortion, low-noise device, having also the ability to drive low-impedance loads to a full voltage swing while maintaining low distortion. Furthermore, it is fully output short-circuit proof. Therefore, this circuit was implemented with a single 5532 chip forming a pair of stereo, inverting amplifiers, having an ac gain of about 3.5 and capable of delivering up to 3.6V peak-to-peak into a 32 Ohm load (corresponding to 50mW RMS) at less than 0.025% total harmonic distortion (1kHz & 10kHz). If we consider that the mean current drawing at a power output of 15mW per channel is around 12-13mA (both channels driven), this Headphone Amplifier will become a must for many DIY enthusiasts needing a High Quality, High Performance portable device.
Sensitivity:
200mV RMS for 15.6mW RMS output
350mV RMS for 50mW RMS output
Maximum undistorted output: 3.6V Peak-to-peak
Frequency response: flat from 40Hz to 20KHz; -2.3dB @ 20Hz
Total harmonic distortion @ 1KHz: <0.025% at all power outputs up to 50mW RMS
Total harmonic distortion @10KHz: <0.02% at all power outputs up to 50mW RMS
Total current drawing @ 9V supply (both channels driven):
Standing current: 8.5mA
Mean current drawing @ 15mW RMS per channel: 12mA
Mean current drawing @ 35mW RMS per channel: 17mA
Source : http://www.ecircuitslab.com/2011/06/portable-9v-headphone-amplifier.html
Egg Timer
This egg timer, which is both simple and functional, shows once again that it is not essential to use a microcontroller for everything these days. The circuit consists of only two ICs from the standard 4000 logic family, a multi-position rotary switch and a few individual components. The combination of a 4040 oscillator/counter and a 4017 decimal counter is certainly not new, but it is an ideal combination for timers that are required to generate long intervals that can be programmed in steps. The circuit can be directly powered from a 9-V battery, without using a voltage regulator. The signalling device is a 12-V buzzer, which generally works quite well even at a much lower voltage.
We won’t explain the operation of the two ICs here; if you would like to know more about this, we recommend consulting the device data sheets. The RC configuration has been selected for the oscillator circuit of the 4060, since the frequencies of standard crystals and resonators would be too high (even 32.768 Hz is much too high), making it impossible to achieve the desired times. With an RC oscillator, it’s also easier to modify the times to suit our purposes. For instance, if the oscillator frequency is reduced by a factor of two, we obtain a range of 1 to 16 minutes in steps of 1 minute. The range is split into two by taking advantage of the fact that the 4017 has an AND gate at its input (with an inverted input).
The two ranges overlap by two steps. The oscillator has been dimensioned such that the 23 divider output (pin 14) has a period of 30 seconds, so IC2 receives a clock pulse every 30 seconds. This means that the oscillator frequency must be set to 8.5333 Hz. The first output of IC2 is active after a reset, so it cannot be used. If S1 is in position I, pin 14 of IC2 is connected to the positive supply line. This input is used as an enable input. Directly after the first pulse from the 4060, the second output of IC2 goes high (which means after exactly half a minute). The sub-sequent outputs become active in turn at intervals of one clock pulse, and thus generate the states for 1 to 4.5 minutes.
In the second range (II) of S1, the ‘enable’ pin of IC2 is connected to the 212 divider output of the 4060 (pin 1). This output goes high 4 minutes after the reset (which is why it is labelled ‘240 s’, instead of the period time of 480 s). Since the 4060 is an asynchronous counter, this output goes high a short time after the 23 output goes low. This delay provides the proper condition for an extra clock pulse for the 4017. The outputs of the 4017 will thus count upwards once. This means that the second output will become active after 4 minutes, with the rest of the outputs becoming active after 4.5 to 8 minutes. The desired timing interval is selected using switch S2.
The output of S2 is connected directly to emitter follower T1, which energizes the buzzer when the level on the wiper of the switch is high. At the same time, the counter of IC1 is disabled via diode D1 by forcing the oscillator input high. The buzzer thus remains active until the circuit is switched off. The first counter output of the 4060 is connected to an LED (D2), which indicates that the circuit is active and the battery not yet exhausted. The blinking rate is approximately 0.5 Hz. The current through the LED is set to a modest 1mA, since this current represents the majority of the current drawn by the circuit.
This ranges from 0.5 to 1.5 mA, with the average current consumption being approximately 1mA while the timer is running. The buzzer used in our prototype increases the current to around 13 mA when it is energized, but this naturally depends on the actual type used. In principle, the circuit will work with any supply voltage between 3 and 16 V. However, the actual supply voltage should be taken into account in selecting the buzzer. The value of the supply voltage also has a small effect on the time interval, but in practice, the deviation proved to be less than 5 percent - which is not likely to matter too much to the eggs.
Continue reading...
We won’t explain the operation of the two ICs here; if you would like to know more about this, we recommend consulting the device data sheets. The RC configuration has been selected for the oscillator circuit of the 4060, since the frequencies of standard crystals and resonators would be too high (even 32.768 Hz is much too high), making it impossible to achieve the desired times. With an RC oscillator, it’s also easier to modify the times to suit our purposes. For instance, if the oscillator frequency is reduced by a factor of two, we obtain a range of 1 to 16 minutes in steps of 1 minute. The range is split into two by taking advantage of the fact that the 4017 has an AND gate at its input (with an inverted input).
The two ranges overlap by two steps. The oscillator has been dimensioned such that the 23 divider output (pin 14) has a period of 30 seconds, so IC2 receives a clock pulse every 30 seconds. This means that the oscillator frequency must be set to 8.5333 Hz. The first output of IC2 is active after a reset, so it cannot be used. If S1 is in position I, pin 14 of IC2 is connected to the positive supply line. This input is used as an enable input. Directly after the first pulse from the 4060, the second output of IC2 goes high (which means after exactly half a minute). The sub-sequent outputs become active in turn at intervals of one clock pulse, and thus generate the states for 1 to 4.5 minutes.In the second range (II) of S1, the ‘enable’ pin of IC2 is connected to the 212 divider output of the 4060 (pin 1). This output goes high 4 minutes after the reset (which is why it is labelled ‘240 s’, instead of the period time of 480 s). Since the 4060 is an asynchronous counter, this output goes high a short time after the 23 output goes low. This delay provides the proper condition for an extra clock pulse for the 4017. The outputs of the 4017 will thus count upwards once. This means that the second output will become active after 4 minutes, with the rest of the outputs becoming active after 4.5 to 8 minutes. The desired timing interval is selected using switch S2.
The output of S2 is connected directly to emitter follower T1, which energizes the buzzer when the level on the wiper of the switch is high. At the same time, the counter of IC1 is disabled via diode D1 by forcing the oscillator input high. The buzzer thus remains active until the circuit is switched off. The first counter output of the 4060 is connected to an LED (D2), which indicates that the circuit is active and the battery not yet exhausted. The blinking rate is approximately 0.5 Hz. The current through the LED is set to a modest 1mA, since this current represents the majority of the current drawn by the circuit.This ranges from 0.5 to 1.5 mA, with the average current consumption being approximately 1mA while the timer is running. The buzzer used in our prototype increases the current to around 13 mA when it is energized, but this naturally depends on the actual type used. In principle, the circuit will work with any supply voltage between 3 and 16 V. However, the actual supply voltage should be taken into account in selecting the buzzer. The value of the supply voltage also has a small effect on the time interval, but in practice, the deviation proved to be less than 5 percent - which is not likely to matter too much to the eggs.
TV Muter Circuit
Many households are still graced by tube-type television sets. If you want to connect one of these large tellies to your stereo system to improve the sound quality, this is usually not a problem because there are plenty of SCART to Cinch adapters available in accessory shops. However, with some sets your pleasure is spoiled by the fact that the audio outputs of the SCART connector are not muted during channel switching. This can sometimes lead to nasty signal spikes, which can cause the loudspeakers of your stereo system to emit irritating popping and cracking noises. In such cases it is a good idea to fit your system with a mute circuit.
Fortunately, the right time to activate the mute circuit is defined by the fact that the happy zapper presses buttons on the remote control to switch channels, and the remote control emits IR signals. There are even inexpensive ready-made IR receiver modules available, such as the TSOP1136 used here, which produce trains of active-low pulses in response to such signals. About the circuit: when no IR signal is present, a capacitor is charged via P2 and a diode. IC1 is a comparator that compares this IR voltage (applied to its non-inverting input on pin 3) to a voltage applied to its other input on pin 2.
TV Muter Circuit diagram :
This reference voltage, which can be adjusted with P1, determines the switching threshold of the comparator. If IC2 receives an IR signal, T2 conducts, and as a result the voltage on C1 drops rapidly below the threshold level set by P1. This causes T1 to change from its previous ‘on’ state to the ‘off’ state. As a result, the relay drops out and the audio link to the stereo system is interrupted for the duration of the noise interval. It’s all quite simple, as you can see. If you do not have a stabilized 5-V supply voltage available, you can use the circuit at the of the schematic diagram (with a 5-V voltage regulator) together with a simple (unstabilised) AC mains adapter that supplies a voltage in the range of 9 V to 12 V to the 7805 (IC3).
You can also use a relay with normally-closed contacts instead of normally-open contacts. In this case, simply swap the signals on pins 2 and 3 of IC1 so the relay pulls in when an IR signal is received instead of dropping out. This saves a bit of power because the relay is only energized during zapping. If you can’t find any worthwhile use for the second comparator of IC1, it’s a good idea to connect pin 6 to +5 V and pin 5 to ground. To improve noise immunity, you should shield the IR sensor so it is not exposed directly to light from a fluorescent fixture.
Source : www.ecircuitslab.com/2011/05/tv-muter-circuit-diagram.html
Saturday, March 30, 2013
Roll Network Cables
Panji Blog How To Make A Rj45 Cable Tester.
568b Straight Through Ethernet Cable.
Eia Network Cable Aug Mar Using Pinout Wiring Crossover Cables.
Ethernet Cable Wiring Diagram Crossover Lg.
Electro Circuit Schema Datasheet Ethernet Cable Wiring.
Ethernet Cable Wiring Diagram.
Gigabit Ethernet Uses Cable In The Same Way As 100base T Ethernet.
Network With Monster Computer Ethernet Cables From Monster Cable.
Cable And An Ethernet Crossover Cable With A T 568b.
Do It Yourself Roll Your Own Network Cables.
The Transistor Tester Circuit
This is a very simple design circuit that can be used to check the hfe of transistors. Both PNP and NPN transistors can be checked using this circuit. Hfe as high as 1000 can be measured by using this circuit. The circuit is based on two constant current sources build around transistors Q1 and Q2. This is the figure of the circuit.
Operation of the circuit is the Q1 is a PNP transistor and the constant current flows in the emitter lead. The value of constant current can be given by the equation; (V D1 -0.6)/ (R2+R4).The POT R4 can be adjusted to get a constant current of 10uA.
The Q2 is an NPN transistor and the constant current flows into the collector lead. The value of this constant current can be given by the equation; (VD2-0.6)/(R3+R5).The POT R5 can be adjusted to get a constant current of 10uA.This constant current provided by the Q1 circuit if the transistor under test is an NPN transistor and by Q2 circuit if the transistor under test is a PNP transistor is fed to the base of transistor under test. This current multiplied by the hfe flows in the collector of the transistor and it will be indicated by the meter. The meter can be directly calibrated to read the hfe of the transistor. The Zener diodes must be rated at least 400mW. J1 and J2 are transistor sockets.
Operation of the circuit is the Q1 is a PNP transistor and the constant current flows in the emitter lead. The value of constant current can be given by the equation; (V D1 -0.6)/ (R2+R4).The POT R4 can be adjusted to get a constant current of 10uA.
The Q2 is an NPN transistor and the constant current flows into the collector lead. The value of this constant current can be given by the equation; (VD2-0.6)/(R3+R5).The POT R5 can be adjusted to get a constant current of 10uA.This constant current provided by the Q1 circuit if the transistor under test is an NPN transistor and by Q2 circuit if the transistor under test is a PNP transistor is fed to the base of transistor under test. This current multiplied by the hfe flows in the collector of the transistor and it will be indicated by the meter. The meter can be directly calibrated to read the hfe of the transistor. The Zener diodes must be rated at least 400mW. J1 and J2 are transistor sockets.
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Flugzeuge De Piper P28 T Flughafen Tonder D Nemark.
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1977 Piper Archer Ii Pa 28 181 180 Hp Dme Gem Graphic Engine Monitor.
Piper Aircraft Will Mit Dem Pipersport Ins Gesch Ft F R Kleine.
Automatic TV Lighting Switch
The author is the happy owner of a television set with built-in Ambilight lighting in the living room. Unfortunately, the television set in the bedroom lacks this feature. To make up for this, the author attached a small lamp to the wall to provide background lighting, This makes watching television a good deal more enjoyable, but it ’s not the ideal solution. Although the TV set can be switched off with the remote control, you still have to get out of bed to switch off the lamp.
Automatic TV Lighting Switch Circuit diagram:
Consequently, the author devised this automatic lighting switch that switches the background light on and off along with the T V set. The entire circuit is fitted in series with the mains cable of the TV set, so there’s no need to tinker with the set. It works as follows: R1 senses the current drawn by the TV set. It has a maximum value of 50 mA in standby mode, rising to around 500 m A when the set is operating. The voltage across R1 is limited by D5 during negative half- cycles and by D1– D4 during positive half-cycles. T he voltage across these four diodes charges capacitor C1 via D6 during positive half-cycles. This voltage drives the internal LED of solid-state switch TRI1 via R2, which causes the internal triac to conduct and pass the mains voltage to the lamp. Diode D7 is not absolutely necessary, but it is recommended because the LED in the solid-state switch is not especially robust and cannot handle reverse polarisation. Fuse F1 protects the solid-state switch against overloads. T he value of use d here (10 Ω) for resistor R1 works nicely with an 82-cm (32 inch) LCD screen.
With smaller sets having lower power consumption, the value of R1 can be increased to 22 or 33 Ω, in which case you should use a 3-watt type. Avoid using an excessively high resistance, as otherwise TRI1 will switch on when the TV set is in standby mode. Some TV sets have a half-wave rectifier in the power supply, which places an unbalanced load on the AC power outlet. If the set only draws current on negative half-cycles, the cir-cuit won’t work properly. In countries with reversible AC power plugs you can correct the problem by simply reversing the plug. Compared with normal triacs, optically cou-pled solid-state relays have poor resistance to high switch-on currents (inrush currents).
For this reason, you should be careful with older-model TV sets with picture tubes (due to demagnetisation circuits). If the relay fails, it usually fails shorted, with the result that the TV background light remains on all the time. If you build this circuit on a piece of perf-board, you must remove all the copper next to conductors and components carrying mains voltage. Use PCB terminal blocks with a spacing of 7.5 mm. This way the separation between the connections on the solder side will also be 3 mm. If you fit the entire arrangement as a Class II device, all parts of the circuit at mains potential must have a separation of at least 6 mm from any metal enclosure or electrically conductive exterior parts that can be touched.
Author :Piet Germing - Copyright : Elektor
Source : http://www.ecircuitslab.com/2012/03/automatic-tv-lighting-switch.html
Pyro Electric Fire Alarm
Here is an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo element to detect fire. The lead zirconate titanate crystals in the piezo element have the property to deform and generate an electric gate protected p-channel MOSFETs in the inputs. It has high speed of performance and low input current requirements.There are two inputs—the non-inverting input (pin 3) connected to the piezo element through diode D7 (OA71) that carries the voltage signal from the piezo element and the inverting input (pin 2) that gets a preset voltage momentarily changes the voltage level at pin 3 of IC1 and its output swings high.
Transistor T1 conducts taking the reset pin 12 of IC2 to ground. IC2 is now enabled and starts oscillating. With the shown values of the oscillating components C3 (0.22μ) and R6 potential when heated, thus converting the piezo element into a heat sensor. The circuit described here is very sensitive. It gives a warning alarm if the room temperature increases more than 10°C. The entire circuit has two sections—the sensor and the power supply section.
Fig. 1: Pyroelectric fire sensor Circuit diagram:
Sensor side circuit. Fig. 1 shows the fire sensor circuit. The front end of the circuit has a sensitive signal amplifier built around IC1 (CA3130). It gives a high output when temperature near the piezo element increases. IC CA3130 is a CMOS operational amplifier with gate protected p-channel MOSFETs in the inputs. It has high speed of performance and low input current requirements. There are two inputs—the non-inverting input (pin 3) connected to the piezo element through diode D7 (OA71) that carries the voltage signal from the piezo element and the inverting input (pin 2) that gets a preset voltage through VR1.
Fig. 2: Power supply with battery backup
By adjusting VR1,it is easy to set the reference voltage level at pin 2. In normal condition, IC1 gives a low output and the remaining circuitry is in a standby state. Capacitor C2 keeps the non-inverting input of IC1 stable,so that even a slight change in voltage level in the inputs can change the output to high. Normally, IC1 gives a low output, keeping transistor T1 non-conducting. Reseting pin 12 of IC2 (CD4060) connected to the collector of transistor T1 gets a high voltage through R5 and IC2 remains disabled. When the piezo element gets heat from fire, asymmetry in its crystals causes a potential change, enabling capacitor C2 to discharge.
It (1M), the first output (Q3) turns high after a few seconds and a red LED2 starts flashing. If heat near the piezo persists, Q7 (pin 14) output of IC2 becomes high after one minute, and the alarm starts beeping. If heat continues, Q9 (pin 15) turns high after four minutes and turns on the relay driver transistor T2. At the same time, diode D8 conducts and IC2 stops oscillating and toggles. The solenoid pump connected to the N/O (normally opened) contact of the relay starts spraying the fire-ceasing foam or water to the possible sites of fire. Power supply circuit. Powe supply section (Fig. 2) comprises a 0-12V, 1A step-down transformer with a standard full-wave rectifier formed by D1 through D4 and filter capacitor C1. A battery backup is provided if the mains supply is cut-offb due to short-circuit and fire. A 12V, 4.5Ah rechargeable battery is used for backup to give sufficient current to the solenoid pump. When mains power is available, diode D5 forward biases.
It provides power to the circuit and also charges the battery through resistor R2, and it limits the charging current to 120 mA. When power fails, diode D5 reverse biases and diode D6 forward biases, giving instant backup to the circuit. LED1 indicates the availability of mains power. Assemble the circuit on a generalpurpose PCB and enclose it in a suitable case. Connect the piezo element to the circuit using a thin insulated wire. Glue the flat side of the piezo element on a 30×30cm aluminium sheet to increase its sensitivity. Fix the sheet with the piezo sensor to the site where protection is needed. The remaining circuit can be fixed at a suitable place. If only the alarm generator is needed, omit the relay driver section.
Author :D. Mohan Kumar :Copyright: EFY
Friday, March 29, 2013
Programmable Pressure Transducer
This circuit is design allows only a small diaphragm deflection sin it has limited elasticity, and this produces only a very small output signal, only about 1% modulation of the bridge resistance elements. This circuit is based on LM4041. This is the figure of the circuit.
The A2 circuit provides for the precision adjustment, via DCP1, of any transducer initial null offset error. To accomplish this, the bridge excitation voltage is programmable attenuated by the R2, R3, R4, R5 network and applied to DCP1. Boosting the ~10mV/psi bridge signal by 100x to a convenient 1V/psi output level is the job of the A3 non-inverting amplifier via its feedback and calibration network consisting of R7 through R9 and DCP2. The range for the zero adjustment voltage is from +22mV to –22mV. The resolution is 172uV and is proportional to the bridge excitation voltage, thus improving the temperature stability of the zero adjustment.
The net result of the combination of transducer and the Figure 4 circuitry is a signal conditioned precision pressure sensor that is compatible (thanks to DCP1 and 2) with full automation of the calibration process, is very low in total power draw (< 1 milli ampere, most of which goes to transducer excitation), and (equally important) is low in cost.
Astable Circuit Produce Pulses Using 555 Timer IC
This is circuit that first introduced by Signetics Corporation as the SE555/NE555 about 1971. Pin connections and functions: (See schematic below for basic circuits). Pin 1 (Ground) – The ground (or common) pin is the most-negative supply potential of the device, which is normally connected to circuit common when operated from positive supply voltages. Pin 2 (Trigger) – This pin is the input which causes the output to go high and begin the timing cycle. Triggering occurs when the trigger input moves from a voltage above 2/3 of the supply voltage to a voltage below 1/3 of the supply. This is the figure of the circuit.
For example using a 12 volt supply, the trigger input voltage must start from above 8 volts and move down to a voltage below 4 volts to begin the timing cycle. The action is level sensitive and the trigger voltage may move very slowly. To avoid retriggering, the trigger voltage must return to a voltage above 1/3 of the supply before the end of the timing cycle in the mono stable mode. Trigger input current is about 0.5 micro amps. Pin 3 (Output) – The output pin of the 555 moves to a high level of 1.7 volts less than the supply voltage when the timing cycle begins. The output returns to a low level near 0 at the end of the cycle. Maximum current from the output at either low or high levels is approximately 200 mA. Pin 4 (Reset): – A low logic level on this pin resets the timer and returns the output to a low state. It is normally connected to the + supply line if not used.
Pin 5 (Control) – This pin allows changing the triggering and threshold voltages by applying an external voltage. When the timer is operating in the astable or oscillating mode, this input could be used to alter or frequency modulate the output. If not in use, it is recommended installing a small capacitor from pin 5 to ground to avoid possible false or erratic triggering from noise effects. Pin 6 (Threshold) – Pin 6 is used to reset the latch and cause the output to go low. Reset occurs when the voltage on this pin moves from a voltage below 1/3 of the supply to a voltage above 2/3 of the supply. The action is level sensitive and can move slowly similar to the trigger voltage. Pin 7 (Discharge) – This pin is an open collector output which is in phase with the main output on pin 3 and has similar current sinking capability. Pin 8 (V +) – This is the positive supply voltage terminal of the 555 timer IC. Supply-voltage operating range is +4.5 volts (minimum) to +16 volts (maximum).
Predator Car LED Indicator Tail Light Chaser Circuit
The following car tail circuit was requested by Mr. Danley Sooknanan, its regarding the designing of a customized car tail light consisting of "running" or chasing LEDs arranged in Yautja language, as viewed in the movie "Predator", over the wrist of the "Alien" being. Lets learn more.....
The email request received from Mr. Danley.
In one of your blogs
The email request received from Mr. Danley.
In one of your blogs
http://homemadecircuitsandschematics.blogspot.com/2011/12/how-to-make-car-led-chasing-tail-light.html
I have question .I want to try the chasing tail lights in my car .I want to add something to the design I need your help.The turn indicator i want to make it as a predator count down timer .
http://www.youtube.com/watch?v=vEBW4TsDyok
Let me explain the design in the predator count down timer their is a bunch of sequential lighting. Now what i want to do is have the indicator led move from one point to the other with the predator pattern of the the count down timer.
I would be greatful if you can help me .
The other project I am thinking about is a Audio Spectrum Analyzer
how i want to do this is place it on the led on the grille .When the music plays the led moves upwards and downwards when the diffrent frequency is played
Here is a pic of the grille
http://www.ebay.com/itm/1988-1989-MAZDA-323-PROTEGE-HONEYCOMB-TYPE-BUMPER-GRILLE-NEW-GRILL-/170844788464
Can you help me with the diagram n listing of the parts I need.
It is been for years I have wanted to do this project but I dont know who to ask for the help on the circuit design .
Now i am greatful for the effort n time u help others with .Thanks a million....
before i forget the predator turn signal the sequential count down mus be a little faster than the video i send you move from one point to the other then all the led will flash n light and the the sequential count down starts again
Please provide me with the exact pattern of the LEDs in lit position for the different sequences. you may send me the drawing of it so that I can understand how the LEDs should be laid down.
Regards.
Regards.
Here is some links i have found
At pin#10 the last predator pattern illuminates. In the following sequences, pin#1, 5 6 and 9 of IC1 become high one after the other....however since these outputs are connected to the base of T1 (see next figure), T1 switches ON and it also switches ON T2.
Due to this operation T2 switches in a flashing mode and initiates a flashing response over all the predator which flash thrice until the sequence reaches pin#11 of IC1.
The following figure shows the method in which the bars of the predator sign may be wired using 3mm high bright red LEDs.
As shown, each of the lines in the signs are made by aligning three 3mm LEDs in series. Once all the lines are aligned with the LEDs, the anodes of each string should be connected with individual current limiting resistors.
The ends of the resistors should be made into a common for different blocks and these points should be connected to the collectors of T3, T4, T5, T6, T7 respectively.
The cathodes of all the LEDs in the blocks should be made into a single common point and connected to ground.
http://scratch.mit.edu/projects/PredatorofWar32/2706511
just click the start button n u will see the display
Once again Thanks for the reply . I am really excited of this project .Looking foward to your reply.......
I think I have understood your requirement, the sequence will keep only one block illuminated at a time while sequencing. After the five sequences are over, all the blocks with the relevant patterns will illuminate together and flash. I hope this is what is required by you.
2 by 13 inches will be enough for the design, however the display will not be understandable from a certain distance may be from 30 feet away.
Ill inform you when its posted.
Thanks!
2 by 13 inches will be enough for the design, however the display will not be understandable from a certain distance may be from 30 feet away.
Ill inform you when its posted.
Thanks!
Good point " the display will not be understandable from a certain distance may be from 30 feet away."
U know i was thinking about that before i read the email.Here is what we can do to tweak this. After the five sequences are over the chasing light patterns comes on the indicator. then the five sequence.............
With this tweak the driver behind can see that the indicator is on .
Thanks a million looking foward to the post .
What is the size of the led ?
OK that means the whole display needs to have a central tail light with the predator design, and also LEFT/RIGHT indicator LED lights over the extreme ends of the board.....right?
or perhaps the predator design can be on the turn signals itself, initially for a couple of seconds it will display the predator signs, after that more LEDs on the same blocks will come on so that the signal becomes more visible even from longer distances.
Here is the mazda 323 tail light .
I tried my hand on a photo editing software
Now this is the concept .In the above After the five sequences are over the chasing light pattern starts then the five sequence ...................
I would have have showed u each of the sequence predator pattern photo but that would take five more pics to do that .I think u understand the concept
If the LED PCB is put over the indicator area, it will block the actual bulb indicator lights of the car because the PCB will be opaque by nature.
Theres Another doubt about the sequencing: when the blocks light up one by one (the previous block shutting-of as the sequence proceeds), the various lines (signs) present on each block will not make any action, the illuminated pattern will remain fixed on each block as the sequence proceeds....is it that way???
Theres Another doubt about the sequencing: when the blocks light up one by one (the previous block shutting-of as the sequence proceeds), the various lines (signs) present on each block will not make any action, the illuminated pattern will remain fixed on each block as the sequence proceeds....is it that way???
One thing I would like to commend u on is your patience and quick reply.
I googled n got infomation about retro fitting the taillight .My tail light has bulbs.The idea is to convert the whole tail light to led (LED PCB)
Now this project is all new to me I just have the ideas.What i want to do I want the chasing light feature as your diagram
http://homemadecircuitsandschematics.blogspot.com/2011/12/how-to-make-car-led-chasing-tail-light.html
Now all we are tweaking is the indicator .The indicator part will be converted to the LED PCB
Now this is the concept .In the above After the five sequences are over the chasing light pattern starts then the five sequence pattern...................
I just have ideas what do u think is the best way to display this on the tail light
The predator countdown has an awesome display.
here are the examples....
http://www.youtube.com/watch?v=GKnSNlNTju4
http://www.youtube.com/watch?v=99drofkfpOo
I was thinking of the indicator do u think it would be better on the red part of the tail light.Your input would be highly appreciated ............
Now everything is clear, ......one last question though, I couldnt follow this statement of yours:
"After the five sequences are over the chasing light pattern starts then the five sequence pattern..................."
What I understood is, the predator signs wouldbe displayed initially in the chasing pattern.....once this chasing gets over, all the sign-blocks wouldilluminate together and flash, may be twice and thrice.......what next?? what should be the function after this??
I think the white sectionwould produce better results.....under the red lens, the red LEDs wouldbecome too much responsive, and therefore difficult to distinguish.
"After the five sequences are over the chasing light pattern starts then the five sequence pattern..................."
What I understood is, the predator signs wouldbe displayed initially in the chasing pattern.....once this chasing gets over, all the sign-blocks wouldilluminate together and flash, may be twice and thrice.......what next?? what should be the function after this??
I think the white sectionwould produce better results.....under the red lens, the red LEDs wouldbecome too much responsive, and therefore difficult to distinguish.
Im really glad that ur taking your time to understand and email me back .Im am truly thankful.
What i meant in the quote after the five sequences are over chasing light pattern starts then the sequence pattern
It is like a cycle or loop
n u are correct "the predator signs would be displayed initially in the chasing pattern.....once this chasing gets over, all the sign-blocks would illuminate together and flash, may be twice and thrice"
Then the predator sign chasing pattern would start all over again. after it it is over all the sign blocks would illuminate together and flash may be twice and thrice then the predator sign chasing pattern .You understand now a loop
Now we are using this circuit for the red part of the lens on the tailight
Thank you!
This project is interesting, and the folks will love to read it when it gets published :)
We had discussed earlier, that the signs wouldnt be understandable from some distance and therefore after the initial sequences are over the background light should start flashing in order to make the light distinguishable to the distant vehicles.....so I was actually referring to this operation, when should this happen? According to me after the sequencing and the flashing of the predator signs finish, the background lights should come into action.
If the predator sign sequences keep repeating, it will interfere with the actual flashing of the background lights. Since the operations are connected with signalling and safety issues, it needs to be taken care of seriously. This is what I was interested to know about, so it is the last part of the confusion.....:)
This project is interesting, and the folks will love to read it when it gets published :)
We had discussed earlier, that the signs wouldnt be understandable from some distance and therefore after the initial sequences are over the background light should start flashing in order to make the light distinguishable to the distant vehicles.....so I was actually referring to this operation, when should this happen? According to me after the sequencing and the flashing of the predator signs finish, the background lights should come into action.
If the predator sign sequences keep repeating, it will interfere with the actual flashing of the background lights. Since the operations are connected with signalling and safety issues, it needs to be taken care of seriously. This is what I was interested to know about, so it is the last part of the confusion.....:)
Okay good that you mention safety, lets do it with your method then .
" According to me after the sequencing and the flashing of the predator signs finish, the background lights should come into action."
so it is a loop cycle - predator signs- backround lights come into action - predator signs
This is just like a send u with the last email with all the pics
Ill do it soon, and inform you when its published....Thanks!
Great looking foward to the post .I have some great ideas for some other projects.
like a spectrum analyser display for a car.
an antiteft device for a car
The Design
As shown in the following circuit diagram, three numbers of IC 4017 have been used for implementing the required sequencing operations of the predator signs as well as the background LED indicator bars.
The different stages of the circuit operation may be understood with these points:
When the turn signal switch is turned ON, the 12V supply passes through the 7812 voltage regulated IC and powers the preceding electronic circuit stages.
N1 along with R1 and C1 forms the clock generator or the oscillator circuit which provides the necessary clocking to pin#14 of IC1 and IC2.
IC1 outputs immediately start sequencing in response to the above clocks.
The sequencing initiates from pin#3 of IC1 to pin#10 Since the predator LED patterns are connected with these outputs via transistor drivers, all of these signs become illuminated one after the other in the given sequence.
T2 now starts providing 12V to all the driver transistors which are responsible for sequencing the predator signs, this action immediately switch ON all the predator signs together.
However the clocks (positive) reaching the base of T2 via D1 forces it to blink with every positive clock from N1.
At this point the logic high from pin11 connects with pin 13 of IC1, locking its sequencing on the spot so that the IC now is unable to sequence any further and gets latched at this position.
But the above logic high prompt the output of N4 to go low, which immediately enables IC2 to begin its own sequencing shifts.
The outputs of IC2 now begins sequencing and illuminates the connected LEDs from pin#3 to pin#11. This sequencing starts repeating, and in the process the logic high at pin#3 of IC2 clocks IC#3 pin#14.
IC3 responds to these clocks and in turn allows its outputs to sequence. When its output sequence reaches at pin#5, the entire system RESETs, because the logic high from pin#5 of IC3 hits pin#15 of IC1.
The entire process begins all over again.
The outputs of IC2 are arranged as small vertical bars using high bright RED LEDs and are put in between the predator sign-block gaps and ahead. When the predator sign stops, these bars take their position and continue the sequencing so that the indications become prominently visible even to the distant vehicles at the rear.
Wiring the Predator Sign LED Pattern
The following figure shows the method in which the bars of the predator sign may be wired using 3mm high bright red LEDs.
As shown, each of the lines in the signs are made by aligning three 3mm LEDs in series. Once all the lines are aligned with the LEDs, the anodes of each string should be connected with individual current limiting resistors.
The ends of the resistors should be made into a common for different blocks and these points should be connected to the collectors of T3, T4, T5, T6, T7 respectively.
The cathodes of all the LEDs in the blocks should be made into a single common point and connected to ground.
Parts List
R1 = 100 pot
R2 = 1M
R3....R12 = 1K
R13...R22 = 150 Ohms
R23....R31 = 1K
D1.....D5 = 1N4148
IC1,2,3 = 4017
IC4 = 7812
N1....N4 = 4093
T1 = BC547
T2 = BC557
T3....T7 = 8050
C1....C4 = 1uF/25V non polar
R1 = 100 pot
R2 = 1M
R3....R12 = 1K
R13...R22 = 150 Ohms
R23....R31 = 1K
D1.....D5 = 1N4148
IC1,2,3 = 4017
IC4 = 7812
N1....N4 = 4093
T1 = BC547
T2 = BC557
T3....T7 = 8050
C1....C4 = 1uF/25V non polar
12 Volt DC Fluorescent Lamp Driver
A number of people have been unable to find the transformer needed for the Black Light project, so I looked around to see if I could find a fluorescent lamp driver that does not require any special components. I finally found one in Electronics Now. Here it is. It uses a normal 120 to 6V stepdown transformer in reverse to step 12V to about 350V to drive a lamp without the need to warm the filaments.
Parts:
C1 100uf 25V Electrolytic Capacitor
C2,C3 0.01uf 25V Ceramic Disc Capacitor
C4 0.01uf 1KV Ceramic Disc Capacitor
R1 1K 1/4W Resistor
R2 2.7K 1/4W Resistor
Q1 IRF510 MOSFET
U1 TLC555 Timer IC
T1 6V 300mA Transformer
LAMP 4W Fluorescent Lamp
MISC Board, Wire, Heatsink For Q1
Notes:
Continue reading...
Parts:C1 100uf 25V Electrolytic Capacitor
C2,C3 0.01uf 25V Ceramic Disc Capacitor
C4 0.01uf 1KV Ceramic Disc Capacitor
R1 1K 1/4W Resistor
R2 2.7K 1/4W Resistor
Q1 IRF510 MOSFET
U1 TLC555 Timer IC
T1 6V 300mA Transformer
LAMP 4W Fluorescent Lamp
MISC Board, Wire, Heatsink For Q1
Notes:
- Q1 must be installed on a heat sink.
- A 240V to 10V transformer will work better then the one in the parts list. The problem is that they are hard to find.
- This circuit can give a nasty (but not too dangerous) shock. Be careful around the output leads.
Non Contact Power Monitor Circuit
This is a design circuit for non-contact AC power monitor for home appliances and laboratory equipment that should remain continuously switched-on. This circuit is built around CMOS IC CD4011 utilizing only a few components. NAND gates N1 and N2 of the IC are wired as an oscillator that drives a piezo buzzer directly. This is the figure of the circuit;
Resistors R2 and R3 and capacitor C2 are the oscillator components. The amplifier comprising transistors T1 and T2 disables the oscillator when mains power is available. In the standby mode, the base of T1 picks up 50Hz mains hum during the positive half cycles of AC and T1 conducts. This provides base current to T2 and it also conducts, pulling the collector to ground potential. As the collectors of T1 and T2 are connected to pin 2 of NAND gate N1 of the oscillator, the oscillator gets disabled when the transistors conduct. Capacitor C1 prevents rise of the collector voltage of T2 again during the negative half cycles. When the power fails, the electrical field around the equipment’s wiring ceases and T1 and T2 turn off. Capacitor C1 starts charging via R1 and preset VR and when it gets sufficiently charged, the oscillator is enabled and the piezo buzzer produces a shrill tone. Resistor R1 protects T2 from short circuit if VR is adjusted to zero resistance. The circuit can be easily assembled on a perforated/breadboard. Use a small plastic case to enclose the circuit and a telescopic antenna as aerial. A 9V battery can be used to power the circuit. Since the circuit draws only a few microamperes current in the standby mode, the battery will last several months.
Thursday, March 28, 2013
Phase Shift Oscillator Circuit Using LM386
This is a design circuit of a simple inexpensive amplitude stabilized phase shift sine wave oscillator which requires one IC package, three transistors and runs off a single supply. This circuit is combination with the RC network comprises a phase shift configuration and oscillates at about 12 kHz. The remaining circuitry provides amplitude stability. Here’s the schematic figure of the circuit.
The high impedance output at Q2s collector is fed to the input of the LM386 via the 10 μF-1M series network. This circuit is using op amp LM386 causes it has fixed gain of 20. The 1M resistor in combination with the internal 50 kΩ unit in the LM386 divides Q2s output by 20. The positive peaks at the amplifier output are rectified and stored in the 5 μF capacitor. This potential is fed to the base of Q3. Q3s collector current will vary with the difference between its base and emitter voltages. Since the emitter voltage is fixed by the LM313 1.2V reference, Q3 performs a comparison function and its collector current modulates Q1s base voltage. Q1, an emitter follower, provides servo controlled drive to the Q2 oscillator.
The high impedance output at Q2s collector is fed to the input of the LM386 via the 10 μF-1M series network. This circuit is using op amp LM386 causes it has fixed gain of 20. The 1M resistor in combination with the internal 50 kΩ unit in the LM386 divides Q2s output by 20. The positive peaks at the amplifier output are rectified and stored in the 5 μF capacitor. This potential is fed to the base of Q3. Q3s collector current will vary with the difference between its base and emitter voltages. Since the emitter voltage is fixed by the LM313 1.2V reference, Q3 performs a comparison function and its collector current modulates Q1s base voltage. Q1, an emitter follower, provides servo controlled drive to the Q2 oscillator.
Fire Alarm Circuit Based on Transistor
This is a design for circuit o f the fire alarm. This circuit is work based on 3 transistors. When there is a fire breakout in the room the temperature increases. This ultra compact and low cost fire alarm senses fire breakout based on this fact. This is the figure of the circuit.
The operation of the circuit will based on this explanation. The transistor BC177 (Q1) is used as the fire sensor here. When the temperature increases the leakage current of this transistor also increases. The circuit is designed so that when there is an increase in the leakage current of Q1, transistor Q2 will get biased. As a result when there is a fire breakout the transistor Q2 will be on. The emitter of Q2 (BC 108) is connected to the base of Q3 (AC 128).So when Q2 is ON Q3 will be also ON. The transistor Q3 drives the relay which is used to drive the load ie, light, bell, horn etc as an indication of the fire. The diode D1 is used as a free wheeling diode to protect it from back EMF generated when relay is switched. All capacitors are electrolytic and must be rated at least 10V.
The load can be connected through the C, NC, NO points of the relay according to your need. The calibration can be done using a soldering iron, and a thermo meter. Switch ON the power supply. Keep the tip of soldering iron near to the Q1.Same time also keep the thermometer close to it. When the temperature reaches your desired value adjust R1 so that relay gets ON. This is not a latching alarm, when the temperature in the vicinity of the sensor decreases below the set point the alarm stops. The circuit can be powered using a 9V battery or a 9V battery eliminator.
The operation of the circuit will based on this explanation. The transistor BC177 (Q1) is used as the fire sensor here. When the temperature increases the leakage current of this transistor also increases. The circuit is designed so that when there is an increase in the leakage current of Q1, transistor Q2 will get biased. As a result when there is a fire breakout the transistor Q2 will be on. The emitter of Q2 (BC 108) is connected to the base of Q3 (AC 128).So when Q2 is ON Q3 will be also ON. The transistor Q3 drives the relay which is used to drive the load ie, light, bell, horn etc as an indication of the fire. The diode D1 is used as a free wheeling diode to protect it from back EMF generated when relay is switched. All capacitors are electrolytic and must be rated at least 10V.
The load can be connected through the C, NC, NO points of the relay according to your need. The calibration can be done using a soldering iron, and a thermo meter. Switch ON the power supply. Keep the tip of soldering iron near to the Q1.Same time also keep the thermometer close to it. When the temperature reaches your desired value adjust R1 so that relay gets ON. This is not a latching alarm, when the temperature in the vicinity of the sensor decreases below the set point the alarm stops. The circuit can be powered using a 9V battery or a 9V battery eliminator.
1978 Ford F 150 Lariat Wiring Diagram
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| 1978 Ford F-150 Lariat Wiring Diagram |
The Part of 1978 Ford F-150 Lariat Wiring Diagram: direct switch, marker light, battery, headlight, light
switch, high beam, indicator, horn relay, yellow wire, green wire, fusible link, starter relay, ignition coil, park light, distributor, ignition module, noise filter, cluth safety switch, alternator indicator, backup light, widshield wiper switch, washer motor, regulator
switch, high beam, indicator, horn relay, yellow wire, green wire, fusible link, starter relay, ignition coil, park light, distributor, ignition module, noise filter, cluth safety switch, alternator indicator, backup light, widshield wiper switch, washer motor, regulator
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