This circuit is from an American 1967 documentation and can be implemented with modern equivalent transistors. The circuit serves as a Q multiplier.
This circuit is from an 80's documentation, making use of PUTs that are not currently common...
This is 4-input audio mixer using an integrated circuit 741 and two more operational amplifiers....
The purpose of this circuit is to power a small fluorescent lamp from from a 12 V battery. The circuit...