Found in 1965 Radio Shack documentation, this circuit has a crystal phone output in the 14.8 kHz range. The coil consists of 200 turns of wire 25 in a 1.5 m side square.
This circuit is from 1990 documentation. When we press D1 the lamp remains on for a time interval that...
Some old multimeters have a high resistance scale that has an internal circuit powered by a 22.5 V...
This circuit, from a 2001 documentation, appears elsewhere on this site. Its purpose is to obtain a...