Crystal Tester (T329E)

This circuit is from a 1964 publication. The circuit tests crystals from 2 to 20 MHz with good accuracy. The power supply is included.

Amplifier with the 4049 (CB4770E)
This different audio amplifier was found in a 90's Electronic Design. The circuit uses components...
NiCad Battery Automotive Charger (CB4978E)
This small automotive NiCad battery charger uses only passive components and has the number of...
Tachometer and Dwell Meter (CB1418E )
This circuit was obtained in an old publication of 1978. The integrated circuit is the critical...