[Wolf] sent in this site a while back, and I thought that this frequency meter how-to looked pretty useful. It’s based on an Atmel AT89C52 and a gutted multi-meter. The circuit isn’t too bad. (The ...

You don’t see them much anymore, but there was a time when any hobbyist who dealt with RF probably had a grid dip meter. The idea was to have an oscillator and measure the grid current as it ...