This circuit was found in a 1965 Radio Shack documentation. The transistors are from that time. The circuit can be implemented with current transistors and lower voltage supply.
Found in American documentation from the 90s, this circuit shows how to derive a signal in the...
The sensor of this circuit is an NTC with a resistance between 200 and 1000 ohms. The resistor R1 must...
This circuit was found in the magazine of radio amateurs 73 in a 90's edition. The components are...