This circuit detects smoke by changing the light falling on the sensor. The circuit was found in the Electronics Experimenter's Handbook of 1991. Optical devices must be used.
This amplifier was found in a Japanese publication in 1972. Transistors are uncommon today, and...
The current of this source is 200 mA at the most, and the output depends on the zener that may...
Found in Mallory documentation from 1968 this circuit uses an integrated circuit from that time. The...