IC audible logic probe circuit based LM339
Here is the old simple logic probe though with a different twist. Instead from representing logic status with LEDs, it makes the work aurally. The logic 1 state, 2 Volts … Read more →
Slot Car Race Referee Circuit
Make this optoelectronic critic and end ever those squabbles over who actually won the competition. Install Q1 and Q3 phototransistors at the end position, exactly in separate roads of your … Read more →
Musical Modulator Circuit
Fill this circuit a simple audio tone, and it provides you back a musical note with a selectable drive, sustain and decay. Input impedance is 10,000 ohms, output impedance 1000 … Read more →
Automatic emergency lighting Circuit
This unit charges a nickel-cadmium battery from the mains to provide a standby power supply for emergency lighting in the event of a mains fail- ure. When the mains supply … Read more →
Simple Audio Amplifier/Oscilator Circuit with Two Transistors
This circuit has two main functions, namely as an audio amplifier and as an oscillator. J1 is a standard 3.5 mm jack connector. The transformers used in this circuit are … Read more →
