Foundations Of Amateur Radio

Foundations of Amateur Radio If you have the need to switch something on and off, a likely first candidate is to get a switch from the local hardware store. The principle is pretty straightforward. You put the switch into the power supply lead and by pushing it on, the two halves of the switch make contact with each other, completing a circuit, and the thing you're switching turns on. It's a lot like having two bits of bare wire that you can touch the ends together. What if you want to remove the human touch from the equation, that is, switch something without having to actually push a switch? A potential candidate for this is a relay. In essence it's exactly the same as a manual switch, except the pushing is done by an electromagnet. The way it works is that you send a current through a coil that is wound around a metal core which results in a magnetic force. This force is used to push or pull the switch open or closed. Now both a manual switch and a relay have moving parts. That means that there is a lim