This circuit was obtained from Linear Technology documentation from the 80's. Powered by 5 V it can be used as a shield. The components are from the era.
This circuit was found in a 1965 General Electric manual. What it does is give a warning if you...
The sensor in this circuit is a BA315 diode. Other diodes can be experimented, but this is one...
This circuit turns on your car's backlight when a vehicle coming from behind gets too close to it...