We found this circuit in a 1980s documentation. Equivalent components can be used. The circuit senses temperatures in the range of 0 to 50º C and uses a transistor as sensor.
This circuit was found in old documentation, however the components used are common today. The...
This circuit is from a 1964 Electronic Design. The sensor is an LDR and the transistors are...
This circuit from Delta Products was published in the May 1974 Radio Electronics magazine. The...