This CMOS circuit for LED displays is from a Radio Electronics magazine from February 1989. The circuit has an enable pulse for storing the value shown on the display.
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...