This is the commercial circuit for the TRF-44 amplifier sold in Japan in the 1960s. The circuit provides a few hundred milliwatts and is intended to be used as small, battery-powered turntables.
We found this circuit in an English magazine from 1976. The magazine no longer exists, but just...
The figure shows a simple way to have emergency power for a 9 V circuit powered by a source. If...
Found in an Electronic Design from the 90's, this circuit supplies voltages according to the...