This circuit uses a crystal phone and can be built with more modern transistors like the BC548. The original circuit is from a 1979 publication and is powered with only two AA or AAA batteries.
This mixer configuration with the 741 operational amplifier can be found on several other circuits in...
Touching the sensor with your fingers, this circuit produces a machine gun sound. The circuit must...
This 13.8 V power supply with 10 A was found in a 1997 documentation. It is intended for the...