Operating in the range of 3 to 100 MHz, this circuit was found in documentation from the 70s. Observe the coil. The field effect transistor is a component of the era.
This polarity test or indicator indicates the polarity of a power line by LEDs. The circuit is...
This is the circuit of a digital clock published in the January 1975 issue of Radio Electronics magazine....
Found in an Elektor from the 90s, this circuit can be powered directly by the power grid. The...