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.
We found this circuit in the April 1975 Radio Electronics magazine. The circuit has a latch and...
We found this sophisticated home alarm in a 1994 documentation. The circuit supports sensors of...
This circuit was found in the 1991 Electronics Experimenter's Handbook. It activates a relay when...