This low speed circuit was obtained in a 1966 Microelectronic Design. The circuit has a 10 MHz passband. The power supply must be symmetrical.
Found on 90's Popular Electronics, this circuit triggers when the microphone picks up a sound. The...
This circuit was found in a 1969’s American documentation. It shows how to use two transistors to form...
Found in a Popular Electronics from the 90's, this circuit can be implemented with almost any...