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 allows you to modify the resolution of a measurement bridge. It was found in the...
In the figure we have a three-phase AC motor control for voltages up to 600 V or 1200 V depending on...
This small experimental transmitter with the CK722 transistors was found in Radio Electronics...