This circuit is from a Radio Electronics from February 1959. The circuit has a speaker output and good sensitivity. Power is supplied from a 9 V battery.
We find this circuit in a documentation for engineers from 1971. The circuit generates rectangular and...
Found in General Electric documentation from 1967, this circuit uses an unusual PUT today. The...
This circuit, which uses a VU-meter with zero in the center of the scale, which is not easy to...