This circuit was found in a British documentation from 1969. It can be implemented with modern transistors. The pass band is 6 MHz.
Varicap or varactor is the basic component used in this circuit of an American 80's documentation. The...
This simple power or speed control for DC Motors uses a Power MOSFET as driver stage and a 4093 IC as...
This 80's circuit uses a small light bulb as an indicator, but an LED with the appropriate resistor...