This humidity sensor indicates the different levels of conduction of the sensors through an LED bar. The circuit is from Popular Electronics and must be powered by cells or battery.
This circuit, found in 2002 documentation, generates a strong audio tone when the light in the...
This circuit uses a variable transformer available at the time. This turns of the windings were...
This is one of the many 7400 oscillators we have in our circuit bank. It is crystal controlled and must be...