Showing posts with label circuit. Show all posts
Showing posts with label circuit. Show all posts
Monday, May 27, 2013
Make this Simple Delay ON Timer Circuit Application Note Included
The post explains a simple delay ON circuit which allows the connected load at the output to be switched ON with some predetermined delay after power switch ON.
The explained circuit can be used for all applications which calls for an initial delay ON feature for the connected load after the mains power is switched ON.
The shown diagram is pretty straightforward yet provides the necessary actions very impressively, moreover the delay period is variable making the set up extremely useful for the proposed applications.
The functioning can be understood with the following points:
Assuming the load which requires the delay ON action being connected across the relay contacts, when power is switched ON, the 12V DC passes via R2 but is unable to reach the base of T1 because initially, C2 acts as a short across ground.
The voltage thus passes through R2, gets dropped to relevant limits and starts charging C2.
Once C2 charges up to a level which develops a potential of 0.3 to 0.6V (+ zener voltage) at the base of T1, T1 is instantly switched ON, toggling T2, and the relay subsequently....finally the load gets switched ON too.
The above process induces the required delay for switching ON the load.
The delay period may be set by appropriately selecting the values of R2 and C2.
R1 ensures that C2 quickly discharges through it so that the circuit attains the stand by position as soon as possible.
D3 blocks the charge from reaching the base of T1.
Parts List
R1 = 610K
R2 = 330K
R3= 10K
R4 = 1K
D1 = 3V zener diode
D2 = 1N4007
D3 = 1N4148
T1 = BC547
T2 = BC557
C2 = 33uF/25V
Relay = SPDT, 12V/400 Ohms
Application Note
Lets learn how the above circuit becomes applicable for solving the following presented issue by one of the keen followers of this blog, Mr. Nishant.
The explained circuit can be used for all applications which calls for an initial delay ON feature for the connected load after the mains power is switched ON.
The shown diagram is pretty straightforward yet provides the necessary actions very impressively, moreover the delay period is variable making the set up extremely useful for the proposed applications.
The functioning can be understood with the following points:
Assuming the load which requires the delay ON action being connected across the relay contacts, when power is switched ON, the 12V DC passes via R2 but is unable to reach the base of T1 because initially, C2 acts as a short across ground.
The voltage thus passes through R2, gets dropped to relevant limits and starts charging C2.
Once C2 charges up to a level which develops a potential of 0.3 to 0.6V (+ zener voltage) at the base of T1, T1 is instantly switched ON, toggling T2, and the relay subsequently....finally the load gets switched ON too.
The above process induces the required delay for switching ON the load.
The delay period may be set by appropriately selecting the values of R2 and C2.
R1 ensures that C2 quickly discharges through it so that the circuit attains the stand by position as soon as possible.
D3 blocks the charge from reaching the base of T1.
Parts List
R1 = 610K
R2 = 330K
R3= 10K
R4 = 1K
D1 = 3V zener diode
D2 = 1N4007
D3 = 1N4148
T1 = BC547
T2 = BC557
C2 = 33uF/25V
Relay = SPDT, 12V/400 Ohms
Application Note
Lets learn how the above circuit becomes applicable for solving the following presented issue by one of the keen followers of this blog, Mr. Nishant.
Hello Sir,
I have a 1KVA automatic voltage stabilizer.It has one defect that when it is switched on, very high voltage is outputted for about 1.5s (therefore cfls and bulb got fused frequently) after that the voltage becomes OK. I have opened the stabilizer it consist of an auto-transformer,4 24V relay each relay connected to a separate circuit(each consisting of 10K preset,BC547,zener diode,BDX53BFP npn darlington pair transistor IC,220uF/63v capacitor,100uF/40V capacitor ,4 diodes and some resistors).These circuits are powered by a step down transformer and output of these circuit are taken across corresponding 100uF/40V capacitor and fed to corresponding relay.What to do in order to tackle the problem.please help me.Hand drawn circuit diagram is attached.
Solution:
The problem in the above circuit might be due to two reasons: one of the relays is switching ON momentarily connecting the wrong contacts with the output, or one of the responsible relays is settling down with the correct voltages a little while after power switch ON.
Since there are more than one relay, tracing out the fault and correcting it can be a bit tedious......the circuit of a delay ON timer explained in the above article could be actually very effective for the discussed purpose.
The connections are rather simple.
Using a 7812 IC, the delay timer can be powered from the existing 24V supply of the stabilizer.
Next, the delay relay N/O contacts may be wired in series with the stabilizer output socket wiring.
The above wiring would instantly take care of the issues as now the output would switch after some time during power witch ONs, allowing enough time for the internal relays to settle down with the correct voltages across their output contacts.
Tuesday, May 14, 2013
Simple 555 Timer circuit diagram
A lot of guys requested a simple timer circuit so this is the circuit.This circuit runs with main IC NE555. you can change the frequencies of the circuit by changing the values of R1, R2,C .This circuit runs with 4.5V. Note : # Dont supply more than 4.5V # Build this on a PCB
Spy FM Transmitter circuit
]
This is so impotent circuit for us,Because we can use this circuit as a spy unit.This circuit can transmit signals about 30m.And the other important thing is the power of this circuit we can operate this circuit with 1.5v to 3v(1.8 mA at 1.5 Volts )
Note
# If you are unable to find the transistor here use these transistors Because here you can use equal transistors such as 2N2222A, BFxxx series, BC109B, C, and even well known BC238.
# Use 1.5v to 3v for this circuit.Dont supply more than 3v(3v can cover the max range 30m)
Monday, May 13, 2013
Stereo line driver circuit
This is the circuit diagram of a low cost stereo line driver is given here. The circuit consists of only two transistors and few passive components. Each BC 109C transistor is wired as an emitter follower for driving each channel. The voltage gain of the emitter follower is unity, but it has a high current gain and low output impedance, ideal for driving long cables. The output impedance is around 16 Ohms at 1KHz.Since voltage gain is unity power amplifiers must be used at the listening end in order to drive loud speakers.
Notes.
* Assemble the circuit on a general purpose PCB.
* The circuit can be powered from a 12V battery or 12V DC power supply.
* The inputs and outputs must be connected with respect to ground as shown in circuit.
* A power amplifier is needed at the listening end because the emitter follower has only unity voltage gain.
* The line driver circuit must be place close to the audio source.
Continue reading...
Notes.
* Assemble the circuit on a general purpose PCB.
* The circuit can be powered from a 12V battery or 12V DC power supply.
* The inputs and outputs must be connected with respect to ground as shown in circuit.
* A power amplifier is needed at the listening end because the emitter follower has only unity voltage gain.
* The line driver circuit must be place close to the audio source.
Friday, April 12, 2013
USB Battery Charger Circuit Rise
In recent 12 monthss, the utilization of USB or Universal Serial Bus as a reliable communiques interface in lots of digital instruments have increased because of its increased pace, size and flexibility. It essentially consists of terminals VBUS(+5V provide), GROUND, D+ and D-. As a complete lot of of the devices run on rechargeable battery, it is now the development to design the charging circuit that makes use of the energy supply from the USB port to charge the rechargeable battery. This function will make the instruments more handy to the users as the tools will get their energy from the bus and requires no outside plug or cables.
![](\"http://www.electronics-project-design.com/images/USBConfiguration.GIF\")
USB Bus Powered Functions
Theres essentially three lessons of USB performs on power that can be derived from the port.
High-Power Bus The excessive energy bus energyed operates derived all its power from the VBUS and cannt draw over 100mA unless its been configured. One time configured, it would possibly probably draw as a lot as 5 unit loads(500mA) by using asking for it in its descriptor. At full load, it must have the flexibility to work between the VBUS voltage of 4.75V and 5.25V.
Low-Power Bus The low energy bus energyed operates derived all its power from the VBUS and should now not draw over one unit load (100mA) in line with the USB usual. It should even have the flexibility to work between the VBUS voltage of 4.40V and 5.25V.
Self-Power Self power performs can draw up to 100mA from the VBUS and the remaining from its outdoor source. This is the easystst to design.
Low-Power Bus The low energy bus energyed operates derived all its power from the VBUS and should now not draw over one unit load (100mA) in line with the USB usual. It should even have the flexibility to work between the VBUS voltage of 4.40V and 5.25V.
Self-Power Self power performs can draw up to 100mA from the VBUS and the remaining from its outdoor source. This is the easystst to design.
![](\"http://www.electronics-project-design.com/images/USBBatteryCharger1.GIF\")
USB Port Powered Battery Charger
This utility circuit makes use of the MCP73853/MCP73855 linear cost management controllers for value delicate utilitys. They are in particular designed for USB softwares and cling to the entire USB specs governing the USB power bus. The circuit below makes use of the MCP73855 to design a USB energyed Lithium Ion/Lithium Polymer battery costr through deriving the energy from the USB port.
Thursday, April 11, 2013
2 X 30Watt home amplifier circuit
Audio amplifier circuit is very suitable for use at home, using a subwoofer speaker, or woofer speaker. Usually, also called home amplifier, audio amplifiers are based on the IC and ic are used still in series with type STK457 STK and besides it also can use the STK459, 460, 461, 463, 465. And each ic has the quality of each one, please look at alldatasheet.com.
C5 = 0.1uF
C8 = 0.1uF
Continue reading...
Part List :
R1 = 22K
R2 = 22K
R3 = 330R
R4 = 33K
R5 = 1K
R6 = 1K
R7 = 4.7R
R8 = 3K3
R9 = 3K3
R10 = 4.7R
R11 = 100R
R12 = 33KR13 = 330R
C1 = 0.1uF
C2 = 0.1uF
C3 = 100uF
C4 = 100uFC5 = 0.1uF
C6 = 47uF
C7 = 47uFC8 = 0.1uF
C9 = 100uF
C10 = 100uFU1 = STK457,STK459, 460, 461, 463, 465.
Sunday, April 7, 2013
TV Remote Tester Circuit
The circuit is very effective to test the remote controls what still works or not, the remote record will be tested using infra red. Examples of the TV remote, AC and others. Please try I am sure 100% will be successful.
 |
| TV Remote Tester Circuit |
The workings of the circuit is very simple, when the infra red sensor receive infrared signals pin 2 sensor will produce a voltage, this voltage will drives the PNP transistor so that the LED lamp and piezo disc (BZ) is active. for the power supply you can use a 9 volt battery and then use IC 7805 or use 1.5 volt batteries x 3
Following the specification of components installed
Transistor BC557
TSOP 1738 Sensor Infra Red
R1 = 10k ohm ¼ watt Resistor
R2 = 1k ohm ¼ watt Resistor
R3 = 1k ohm ¼ watt Resistor
BZ = piezo disc
led
Saturday, April 6, 2013
Stereo TDA2822 audio power amplifier circuit
In this series I use IC tda2822M as the main amplifier, but if you want to use in addition to IC TDA2822M you can use ic I mentioned this is KA2209, NJM2073, U2822B, U2823B. Output is issued no more than 4W, which had low output. Supply voltage from 3 volts to 16 volts.
Below its schematics of TDA2822 stereo audio power amplifier
R1 = 4.7R
R2 = 4.7R
C1 = 1uF
C2 = 100uF
C3 = 100uF
C4 = 0.1uF
C5 = 470uF
C6 = 1uF
C7 = 100uF
C8 = 0.1uF
C7 = 100uF
C8 = 0.1uF
C9 = 470uF
ICs = KA2209 , NJM2073 , TDA2822 , U2822B , U2823B
Friday, April 5, 2013
Make this Automatic 10 Watt to 1000 Watt LED Emergency Light Circuit
The following post explains a very simple yet an outstanding automatic 1 watt to 1000 watt emergency lamp circuit. The circuit also includes an automatic over voltage and low voltage battery shut off feature.
The entire circuit functioning may be understood with the following points:
Referring the below given circuit diagram, the transformer, bridge and the associated 100uF/25V capacitor forms a standard step down AC to DC power supply circuit.
The bottom SPDT relay is directly connected with the above power supply output such that it remains activated when mains is connected with the circuit.
In the above situation, the N/O contacts of the relay stay connected which keeps the LED shut OFF (since its connected with the N/C of the relay).
This takes care of the LED switching, making sure than the LEDs are switched ON only in the absence of mains power.
However, the positive from the battery is not directly connected with the LED module, rather it comes via another relay N/O contacts (the upper relay). This relay is integrated with a high/low voltage sensor circuit stationed for detecting the battery voltage conditions.
Supposing the battery is in a discharged condition, switching ON the mains keeps the relay deactivated so that the the rectified DC can reach the battery via the upper relay N/C contacts initiating the charging process of the connected battery.
When the battery voltages reaches the "full charge" potential, as per the setting of the 10 K preset, the relay trips and joins with the battery through its N/O contacts.
Now in the above situation if the mains fails, the LED module is able to get powered via the above relay and the lower relay N/O contacts and get illuminated.
Since relays are used, the power handling capacity becomes sufficiently high. The circuit is thus able to support in excess of 1000 watts of power (lamp), provided the relay contacts are appropriately rated for the preferred load.
The entire circuit functioning may be understood with the following points:
Referring the below given circuit diagram, the transformer, bridge and the associated 100uF/25V capacitor forms a standard step down AC to DC power supply circuit.
The bottom SPDT relay is directly connected with the above power supply output such that it remains activated when mains is connected with the circuit.
In the above situation, the N/O contacts of the relay stay connected which keeps the LED shut OFF (since its connected with the N/C of the relay).
This takes care of the LED switching, making sure than the LEDs are switched ON only in the absence of mains power.
However, the positive from the battery is not directly connected with the LED module, rather it comes via another relay N/O contacts (the upper relay). This relay is integrated with a high/low voltage sensor circuit stationed for detecting the battery voltage conditions.
Supposing the battery is in a discharged condition, switching ON the mains keeps the relay deactivated so that the the rectified DC can reach the battery via the upper relay N/C contacts initiating the charging process of the connected battery.
When the battery voltages reaches the "full charge" potential, as per the setting of the 10 K preset, the relay trips and joins with the battery through its N/O contacts.
Now in the above situation if the mains fails, the LED module is able to get powered via the above relay and the lower relay N/O contacts and get illuminated.
Since relays are used, the power handling capacity becomes sufficiently high. The circuit is thus able to support in excess of 1000 watts of power (lamp), provided the relay contacts are appropriately rated for the preferred load.
Park Aid Modification Circuit
Three-step beeps signal bumper-barrier distance, Infra-red operation, indoor use
This modification was designed on request: some people prefer an audible alert instead of looking at the LED display, making easier the parking operation. The original Park-aid circuit was retained, but please note that the input pins of IC2B, IC2C and IC2D are reversed. LEDs D5, D6 and D7, as also resistors R12, R13 and R14 are omitted. IC2B, IC2C and IC2D outputs drive resistors R15, R16 and R17 through D8, D9 and D10 respectively, in order to change the time constant of a low frequency oscillator based on the 555 timer IC4. This allows the Piezo sounder to start beeping at about 2 times per second when bumper-wall distance is about 20 cm., then to increase the beeps to about 3 per second when bumper-wall distance is about 10 cm. and finally to increase further the beeps frequency to more than 4 beeps per second when the distance is about 6 cm. or less.
Circuit diagram:
Park-Aid Modification Circuit Diagram
Parts:
R15_____________3K3 1/4W Resistor
R16___________330K 1/4W Resistor
R17___________470K 1/4W Resistor
R18___________150K 1/4W Resistor
C6______________1µF 63V Electrolytic or Polyester Capacitor
D8,D9,D10____1N4148 75V 150mA Diodes
IC4_____________555 Timer IC
BZ1___________Piezo sounder (incorporating 3KHz oscillator)
Source : www.redcircuits.com
Variable Brightness AC Lamp Circuit
This circuit is based on SCR operation to control the lamp using slowly intensity. The intensity of a 120 volt light bulbs by controlling the time that the AC line voltage is applied to the lamp during each half cycle. The circuit is directly connected to the AC power line and should be placed inside an enclosure that will prevent direct contact with any of the components. To avoid electrical shock, do not touch any part of the circuit while it is connected to the AC power line. This is figure of the circuit;
How is the circuit will work? This circuit using transistor NPN. A couple NPN transistors are used to detect the beginning of each half cycle and trigger a delay timer which in turn triggers the SCR at the end of the delay time. The delay time is established by a current source which is controlled by a 4017 decade counter. The first count (pin 3) sets the current to a minimum which corresponds to about 7 milliseconds of delay, or most of the half cycle time so that the lamp is almost off. Full brightness is obtained on the sixth count (pin 1) which is not connected so that the current will be maximum and provide a minimum delay and trigger the SCR near the beginning of the cycle. The remaining 8 counts increment the brightness 4 steps up and 4 steps down between maximum and minimum. Each step up or down provides about twice or half the power, so that the intensity appears to change linearly. The brightness of each step can be adjusted with the 4 resistors (4.3K, 4.7K, 5.6K, 7.5K) connected to the counter outputs.
How is the circuit will work? This circuit using transistor NPN. A couple NPN transistors are used to detect the beginning of each half cycle and trigger a delay timer which in turn triggers the SCR at the end of the delay time. The delay time is established by a current source which is controlled by a 4017 decade counter. The first count (pin 3) sets the current to a minimum which corresponds to about 7 milliseconds of delay, or most of the half cycle time so that the lamp is almost off. Full brightness is obtained on the sixth count (pin 1) which is not connected so that the current will be maximum and provide a minimum delay and trigger the SCR near the beginning of the cycle. The remaining 8 counts increment the brightness 4 steps up and 4 steps down between maximum and minimum. Each step up or down provides about twice or half the power, so that the intensity appears to change linearly. The brightness of each step can be adjusted with the 4 resistors (4.3K, 4.7K, 5.6K, 7.5K) connected to the counter outputs.
Monday, April 1, 2013
Headphone amplifier circuit
Headphone amplifier circuit with op amp ic OPA134, 2134, NE5532, 5534.
 |
| Headphone amplifier circuit with op amp |
Automatic Mains Disconnect Circuit
Downloading and CD-burning programs usually provide the option of automatically shutting down the PC on completion of their tasks. However, this energy-saving feature is of little benefit if even after the PC has been switched off, all of the peripheral equipment remains connected to the mains and happily consumes watt-hours. The circuit shown here provides a solution to this dilemma. It is connected ahead of the power strip and connects or disconnects mains power for all of the equipment via a power relay. A connection to a 12-V PC fan (which may be the processor fan or the fan for the chipset, if the latter is present) indicates whether the PC is switched on.
If you are certain that the 12-V power supply voltage is switched off when the PC is in the sleep mode, you can use this connection instead. To switch everything on, press the Start button to cause the power relay to be energized and provide mains voltage to all of the equipment. If the PC has an ATX board, its Power switch must be pressed at the same time to cause the PC to start up. When the PC fan starts to run, low-power relay Re1 engages and takes over the function of the Start switch, which can then be released. This state is stable. If the PC switches to the sleep state, the 12-V voltage drops out.
The electrolytic capacitor ensures that Re1 remains engaged for a short time, after which it drops out, followed by the power relay. D1 prevents the electrolytic capacitor from discharging through the connected fan, and D2 is the usual freewheeling diode. The system is disconnected from both mains leads and is thus completely de-energized. Be sure to select components that are suitable for their tasks. Naturally, the contacts of Re2 should be rated to handle the total current drawn by all of the peripheral equipment and the PC, and the relay coil must be suitable for use with mains voltage (6 mm minimum separation between coil and contacts).
A low-power 12-V relay that can switch mains voltage is adequate for Re2. The Start pushbutton switch is connected to the mains voltage, so a 230-V type must be used. The circuit board layout and enclosure must also be designed in accordance with safety regulations. A separation of at least 6 mm must be maintained between all components carrying mains voltage and the low-voltage components, and the enclosure must be completely free of risk of electrical shock. With a bit of skill, the circuit can be fitted into a power bar with a built-in switch, if the switch is replaced by a pushbutton switch having the same mounting dimensions.
Note:
- The circuit is not suitable for use with deskjet printers that can only be switched on and off by a front panel button.
Source : www.extremecircuits.net
Touch Switch Circuit Using 555 IC
This is a circuit for touch switch circuit. This circuit is almost same with touch door alarm. This circuit uses a 555 timer as the bases of the touch switch circuit. This is the figure of the circuit.
The operation of this circuit is begin, when the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and the buzzer for a certain period of time. The time that the LED and the buzzer is on is based on the values of the capacitor and resistor connected to pin 6 & 7. The 10 M resistor is on pin 2 causes the circuit to be very sensitive to the touch.
The operation of this circuit is begin, when the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and the buzzer for a certain period of time. The time that the LED and the buzzer is on is based on the values of the capacitor and resistor connected to pin 6 & 7. The 10 M resistor is on pin 2 causes the circuit to be very sensitive to the touch.
Sunday, March 31, 2013
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
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.
Friday, March 29, 2013
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
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.
Subscribe to:
Posts (Atom)