The voltages in an adjusted range in the trimpots are indicated by 3 LEDs. The LEDs indicate when the voltage is below the range, above the range and in the range.
This receiver for listening to headphones and 2-battery power was found in Japanese documentation from the...
This circuit was found in a Texas Instruments optoelectronics manual and can work with any...
This circuit activates a relay when raindrops fall on the sensor. The circuit is from 1960...