The operational amplifier of this circuit can be the 741. The circuit has very low consumption and can be powered by two 9-B batteries. Low voltage amplifiers can be used.
In the circuit that uses a PIC16F84, the audio present at the input will have its level controlled by...
This circuit was obtained in a June 1987 magazine Hands-On. It is a circuit that indicates on two...
This circuit is from a cookbook to timers. The circuit is triggered by an external signal and,...