What are Vacuum Tubes, Anyway?
A vacuum tube is a glass bulb (like a light bulb) with all the air exhausted from it, which is then carefully refilled with *magic*. Seriously, vacuum tubes work due to an interesting phenomenon called Thermionic Emission. Basically, a physics fact that a heated piece of metal in a vacuum will emit excess electrons. Controlling this emission is key to a vacuum tube’s operation. Most of the world (except the US) calls them “valves”. This is probably the easiest model to understand. A tube is a “valve” for electrons. Consider the model of your hand working the valve of your garden hose. As your hand turns the valve on and off, the flow from the hose turns on and off. Although your hand would not be able to control the output from the end of the hose, (try stopping a garden hose by putting your hand on the end!) the movement of your hand on the valve easily controls the hose. So, a small input (hand on valve) that controls a large output (hose end) = amplification = Tube Power! The big di
