The sensors in this circuit that triggers when the temperature goes out of a certain range are common diodes. The circuit is from the 1991 Reista Electronics Experimenter's Handbook.
This circuit is a driver for R-2R network of AD converters. We found it in manufacturer...
This circuit was found in an American publication from the 60's. The transistor is made of...
This circuit produces an audio tone on the speaker or magnetic capsule. Rx must be such that added...