This circuit covers 400 kHz to 40 MHz in three bands according to the selected coil. The double MOSFET allows equivalent, since the original is not easy to obtain.
Found in a 1968 US publication, this circuit is designed to measure very weak signals. The...
The sensor can be made using two bare wire or two screen with a piece of tisse between them. One...
This circuit serves as a binary demonstrator using 3 LEDs. The circuit can be scaled up for a...