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 circuit decodes a 1800 Hz tone used in communications. The circuit is from an American...
These two circuits were found in Radio Electronics magazine from February 1960. The transistor is a power...
With the development and availability of small LCD screens for automotive use, especially in...