This unusual circuit from a Popular Electronics of the 90s uses LED indicators, operating as a bridge. The components used are common. It is based on the tuning of the signal by a PLL.
We found this circuit in a 1997 documentation. Power transistors must have good heat sinks. The...
This old circuit is from the era of analog televisions, serving for technicians to make...
e find this circuit in documentation for radio amateurs of 1974. The unijunction transistor can be...