- on Miscellaneous Electronics
- Published in issue 12/2002 on page 0
This circuit represents a general-purpose automatic shut-off switch. The author uses it in his car to ensure that any lamp left on by accident (boot lamp, interior lamp etc.) does not drain the battery while the car is parked in the garage for a few days. Of course, it can also be used in a large variety of other applications.The operating principle is both simple and effective. The operational amplifier is wired as a comparator.