Metal locator (CB7506E)

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

Digital Volume Control with PIC (CB17627E)
This circuit is an excellent application for the PIC in audio, but the reader who intends to do...
10 W amplifier (CB9905E)
To a 16-0hm load, this amplifier provides a power of 10 W. We found this circuit in a Motorola...
TTL Output Magnetic Reader (CB14249E)
This reader with TTL logic compatible output uses an LM139 comparator. The circuit was found in...