We found this circuit in an old English documentation. Transistors support modern equivalents. The circuit converts signals in the 5 to 15 MHz band for tuning into a common medium wave radio.
The figure shows how to use a 3-winding transformer to switch outputs with different voltages by...
This 80's circuit, suggested in Texas Insrtruments documentation, uses a Hall effect sensor. The...
This circuit was found in a 1966 publication. Its purpose is to identify high voltages by lighting a...