Free electronic circuit design and schematic diagram
This is Simple Code Lock circuit. This circuit will turn on a relay when the 8-way DIP switches receives the correct code. Here is the schematic diagram of the circuit: There are two different types of DIP, they are piano-key DIP sw and 8-way DIP sw. This circuit will not draw the current if the switch is kept off. This […]
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This is circuit of Clap Triggered Switch. When the circuit detects tap, or short whistle or a clap, this circuit will toggle the LEDs. 33k and 5K6 charge The second 10u. The negative excursion of the waveform takes the positive end of the 10u towards the 0v rail, when a sound is detected. the two 1N4148 diodes will be pulled […]
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This is Auto OFF Light circuit. After the switch is pressed, the bulb is kept illuminated for a few seconds. To increase the “ON” time, The 10k should be replaced by 100k. Here is the circuit: You can use this delayed auto-off lamp circuit to give temporary lighting for your stairway, or your dashboard, your bookshelf, or many more.
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This is Fast Logarithmic Amplifier circuit. Dynamic range of This circuit has is 80 dB. This circuit is configured to optimize speed rather than dynamic range. To allow the use of feed forward compensation1 on an LM101A operational amplifier, this circuit uses Transistor Q1 that is connected with diode. This compensation can increase the slew rate and extends the bandwidth […]
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This is a circuit of Log Converter with 100dB Dynamic Range. This circuit can give a a logarithmic output voltage for a linear input current. This circuit use an LM108 operational amplifier with Transistor Q1 as non-linear feedback element. R1 and R2 are used as divider. Negative feedback is applied to the emitter base junction of Q2 and the emitter […]
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This is a RS232 Line Driver Power Supply circuit. This circuit can gives an output of ± 12V at ± 40 mA and only requires an input voltage as low as 4.2V. The efficiency of this circuit is better than 70%. This circuit provides a line regulation of ± 0.08% and a load regulation of ± 1.25% (from 10% to […]
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Field strength meter is a “must have” equipment if you’re dealing with radio transmitter electronics. Here is one example of this kind of circuit that works for 2.4 GHz band: An optional amplifier can be inserted after the rectification, so it can be used to boost small signal. This circuit works only for short distance transmitter since the signal must […]
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