This circuit was obtained in a 1999 English magazine. We can easily assemble it with a BD136 or even TIP32 transistor and its supply can be made with voltages from 9 to 12 V.
This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V...
This commercial medium and short-wave radio was manufactured in Japan in the 60s. The circuit has...
General Electric suggests this circuit in an 80's documentation. The circuit makes use of PUTs...