Two-tube regenerative receiver (T1595E)

This circuit is from a Radio Electronics from 1949. The circuit is battery powered and has high impedance listening.

Accented Metronome (CB4369E)
We found this circuit in an English magazine from 1976. The magazine no longer exists, but just...
Backup for batteries (CB24731E)
The figure shows a simple way to have emergency power for a 9 V circuit powered by a source. If...
Voltage reference (CB21214E)
Found in an Electronic Design from the 90's, this circuit supplies voltages according to the...