FM Tracking transmitter

jacky March 8, 2012 12 Comments
Description. The circuit presented her will transmit a audio tone in the FM  band. The circuit can be used as a tracking signal transmitter or a remote control transmitter. The circuit uses only easily available components and any one...
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Fire alarm using thermistor & NE555

jacky March 8, 2012 53 Comments
Description. Many fire alarm circuits are presented here,but this time a new circuit using a thermistor and a timer to do the trick. The circuit is as simple and straight forward so that, it can be easily implemented. The...
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High & Low voltage cut-off with delay& alarm

jacky March 8, 2012 101 Comments
Description. This straight forward circuit will protect electrical appliances from over voltage as well as under voltage. The circuit also produces an alarm when the power supply comes back. An ideal circuit for home to protect your valuable equipments...
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Variable frequency oscillator

jacky March 8, 2012 1 Comment
Description. Here is a simple variable frequency circuit based on timer NE555. Here NE55 is wired as an astable multivibrator, whose output frequency can be varied by varying a potentiometer. This circuit is a must in the work bench...
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Scoring game circuit

jacky January 24, 2012 13 Comments
Description. A simple scoring game circuit that can be used for all occasions when a dice is needed.The circuit is based on a NE555 timer,a 74LS192 counter,a74LS247 decoder and a & segment LED display.The timer IC1 will produce the...
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Light to Frequency converter circuit

jacky February 28, 2011 1 Comment
A simple Light to Frequency Converter Introduction. Here is the circuit diagram of a effective light to frequency converter circuit that can be used for variety of applications such as light intensity measurement,fun etc. The circuit is based on...
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Dual Tone Train Horn Circuit

jacky February 22, 2011 3 Comments
Description. A dual tone train horn simulator circuit can be made using two NE 555 timers connected in cascade.Here instead of using two NE 555 timers a single NE 556 timer is used which is a nothing but two...
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InfraRed (IR) Sensor/Detector

jacky November 22, 2011 11 Comments
InfraRed (IR) Sensor/Detector Circuit Description. The circuit shows that the output of IC1 555 IC,which is designed for a duty cycle of 0.8mSec,with a frequency of 120Hz and 300 mA peak current, is used to drive the infra red...
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Fridge Door Alarm

jacky November 22, 2011 10 Comments
Fridge Door Alarm Circuit Description. This is a fridge door alarm circuit, which produces an audible alarm when fridge is left open for a preset time. This versatile alarm is based  on two 555 timer IC’s. Both ICs are...
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Digital Stop Watch

jacky November 10, 2011 69 Comments
Make a Digital Stop Watch Description A digital stop watch built around timer IC LM555 and 4-digit counter IC MM74C926  with multiplexed 7-segment LED display. MM74C926 consists of a 4-digit counter, an internal output latch, npn output sourcing drivers...
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