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 siren produces an intermitent sound given by the characteristics of the two oscillators using the...
This circuit for some amps was found in a 90s Radio Electronics. The voltage can be between 6 and 25 V...
This circuit was found in a 90s Electronic Engineering. The circuit has the tube's critical...