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.
In the figure we have the astable configuration for the 4093 that serves as a clock for...
This circuit was found in Radio Electronics from the 90s. The circuit employs a transconductance device and...
VR can be from 50 to 220k it is recommended to connect a 100-ohm resistor in series. The lamp may...