Most of us learned to design circuits with schematics. But if you get to a certain level of complexity, schematics are a pain. Modern designers — especially for digital circuits — ...

A standard electret microphone can detect sub-audio "sounds" when some simple equalization circuitry is added.

How do you know that your patch cables are good? For simple jumper wires, a multimeter is about all you need to know for sure. But things can get weird in the RF world, in which case you might ...