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.
We found this circuit in an American publication from the 1990s. Any FET can be used. The circuit...
This circuit can be used as an optical switch or photosensor to excite TTL logic. The transistor can be...
This sensitive circuit was found in a Texas Instruments optoelectronics manual. The transistors can be...