Found in the 1975 RCA tube manual, this circuit appears elsewhere in this section. The circuit uses contemporary components and is powered by the power grid.
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...