Found in RCA documentation from the 90s, this circuit uses components from that time. CA3019 is uncommon today and can be replaced by discrete diodes.
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...