Metal locator (CB7506E)

This simple metal detector was found in a 1960 Sylvania transistor manual. The phone must be high impedance or crystal.

Flashing Timer Switch (CB16959E)
This circuit is from 1990 documentation. When we press D1 the lamp remains on for a time interval that...
22.5 Volt Power Supply (CB13004E)
Some old multimeters have a high resistance scale that has an internal circuit powered by a 22.5 V...
Voltage Doubler CMOS (CB17618E)
This circuit, from a 2001 documentation, appears elsewhere on this site. Its purpose is to obtain a...