Mini no breake (CB22151E)

This circuit was found in old English documentation. When the main power is interrupted, the battery continues to supply the charging circuit.

Low Impedance Microphone Preamplifier (CB10675E)
This circuit is from a Popular Electronics from April 1991. The magazine no longer exists, but the...
Wien bridge oscillator (CB21864E)
This Vienna bridge multi-band oscillator circuit was found in a 1974 Ferranti transistor manual. The...
Infrared Transmitter (CB6370E)
This circuit was found in a Hands On Electronics with the suggested application an optical link for...