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 enables the bilateral command of triacs with the use of low current switches. The...
The figure shows a way to apply gain control to the LM3600 OTA. The circuit is from a Radio...
This configuration was found in a 1990s documentation. Modern operational amplifiers can be used...