This converter for the 150 MHz band was found in an American documentation. Transistors are uncommon today and equivalents can be used.
Found in a magazine 73 for radio amateurs of the 90s, this circuit converts a continuous voltage and...
The sensor of this circuit is an NTC with a resistance between 200 and 1000 ohms. The resistor R1 must...
This circuit controls two relays from a single temperature sensor. The first fires when the...