This circuit that uses potentiometer tuning, was found in a documentation from the 80's. The integrated circuit used is from that time and is a not common today.
This circuit was discovered in an English publication in 1979. The circuit can still be assembled with...
This circuit is the digital indicator for the previous circuit and can be used with similar...
This circuit tests crystals up to a few megahertz with ease. The circuit is from a 1977...