The L1 coil is formed by 4 turns of wire 20 in the form of 0.5 to 0.6 cm without core. The circuit is from an 80's documentation. The range reaches a few tens of meters.
This medium wave commercial receiver from the 1960s was found in a Japanese publication at the...
Found in an American circuit manual from the 1970s, this circuit can use any general-purpose transistor....
We found in this American documentation this circuit for activating common cathode displays. In it we...