We found this circuit in an old documentation. Its purpose is to turn on warning lights when the vehicle in a garage touches or passes a sensing bar preventing it from hitting the wall.
We found this circuit in a 90's Radio Electronics. The low power circuit activates a 12 V relay...
This circuit sources a Constant current to a load. The current is determined by R2. In the...
This page shows a crystal oscillator for 2 MHz. Other frequencies can be produced depending on the...