In the days before semiconductor diodes, transistors, or even vacuum tubes, mechanical means were used for doing many of the same things. But there’s still plenty of fun to be had in using those ...

Getting back to basics is a great way to teach yourself about a technology. We see it all the time with computers built from NAND gates or even discrete transistors. It’s the same for radio – ...

The coherer effect is a phenomenon in which contact resistance rapidly decreases due to electrical breakdown of the contact film. This coherer effect can be easily confirmed using aluminum foil or a ...

How to make, a Modern Coherer and a Brief Review of its History and Theory ...