Freeze Alarm (CB14454E)

The circuit of a 1968 publication can be implemented with more modern transistors such as BC548 for NPN and BC558 for PNP.

Wien bridge oscillator (CB21864E)
This Vienna bridge multi-band oscillator circuit was found in a 1974 Ferranti transistor manual. The...
Metal detector (CB7888E)
This circuit was found in a 1970s RCA publication. Transistors support modern equivalent types....
Sound Voltmeter (CB25975E)
This circuit was found in the September 1996 issue of Electronics Now magazine. The sound provided has...