Grounded

There's been much talk lately about grounds, or, perhaps grounding is just something that's recently caught my fancy and that's why I believe there's been increased chatter. Whatever the case, it has captured my attention and I thought we'd spend a minute thinking about ground. So, what is ground? It could be coffee after it's brewed, dirt in the backyard, or a description of the lowest point in a circuit. Let's go with the latter since I know little about coffee and less about dirt. Today the term ground, as it refers to electrical circuits, is a generic term that has many meanings, but it wasn't always so. In the early days of telegraph wires, somewhere around the late 1800's, it had been observed that it wasn't always necessary to build two wires systems. In the days when wire was a scarce commodity, this was a big deal. Turns out designers could string just one wire between telegraph stations and use the ground (Earth) as the second wire. This worked great for most of the year, but soon trouble erupted. Summer's dried out the earth and it became less of an electrical conductor, and telegraph and telephone conversations started failing at that time of year. The situation got so bad that in populated areas where communications were critical, they often poured water on the ground to help signals flow through it. In fact, over time, they abandoned the idea of using Earth as the second wire in the two-wire system and returned to what worked always, two wires. Ground doesn't always have to involve the Earth. Think of your cell phone or any battery operated device. It too has a "ground" but there's no connection with the Earth. In electrical terms, we more properly refer to ground on a battery device as the common. But, whatever you call it, ground, Earth, or common, the term refers to the lowest point in the circuit. The point which we consider to be zero. Achieving a good ground has major ramifications for stereo systems. Noise, hums, poor performance can result in less than solid grounds and tomorrow we'll delve a little further.