This circuit is from an American 80's documentation. The integrated circuit is from the time and the sensor consists of a smoke chamber measuring its transparency change.
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...
This simple 1 transistor radio was found in Raytheon's transistor manual. The transistor is...
This power supply was described in an article in Radio Electronics magazine from July 1968. The...