Gain 10 Amplifier (CB25636E)

Using a general-purpose transistor this AC amplifier was found in the November 1993 issue of Electronics Now.

Simple Intercom (CB16597E)
This very simple circuit must use coal microphones of the type found in very old equipment. The...
Touch switch (CB9375E)
This biestable circuit was found in a Popular Electronics from the 90s. The circuit has an unusual...
2 to 10 000 Hz Programmable Clock (CB6461E)
This circuit was found in a 1969 US documentation. It provides a signal that can be externally...