Found in 90s Radio Electronics, this small transmitter has a good range. L1 is formed by 3 + 3 turns of wire 24 around a pencil as a reference.
This circuit was obtained from an English publication from the 70's. The circuit is still current for...
This circuit was found in a 1979 magazine. We can use any JFET like MPF102 or BF245. The relay is 12 V...
Found in Motorola documentation from the 90s, this circuit can be implemented with current...