This circuit turns off after a time given by capacitor C1. This component can have from 1 to 1,000 uF depending on the desired time. The circuit is from an Electronics Now from June 1995.
This simple photometer uses a 0-200 µA galvanometer as indicator. The sensor is a common LDR and...
This circuit was found in a 1964 Electronic Design. The circuit makes use of transistors of the...
Found in old documentation, this circuit is tuned to pass signals below 245 Hz with a level of...