The mystery of adding LED lights to a modern BMW with CAN Bus (Controller Area Network) electrical system is easy to resolve. The “smart” CAN Bus smells a rat when you pop in an LED brake light or ...

I needed a simple LED indicator showing that a particular voltage level had been reached—specifically, that a capacitor had charged to a particular potential. I was convinced that there must be a way ...

This LED DC voltage indicator circuit is a voltmeter, rather than simply a battery tester. As such it may measure voltages as low as 3V. It utilizes venerable LM741 operational amplifiers applied as ...