Found in 90s Popular Electronics, this circuit uses common general-purpose transistors in a configuration that has been extensively explored on this site and in our articles.
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...