Published in a February 1978 Radio Electronics magazine article, this digital circuit uses some of the integrated circuits of the time. The circuit uses a LED bargraph.
This amplifier was found in a Japanese publication in 1972. Transistors are uncommon today, and...
The current of this source is 200 mA at the most, and the output depends on the zener that may...
Found in Mallory documentation from 1968 this circuit uses an integrated circuit from that time. The...