Electronic Principles

Many people obviously work with electronics every day; from appliances, to cars, to cellphones, to computers, and the list goes on. Many have had "official" electronics/electrical training. Many have no basic training at all. Some learned by just taking things apart to see how they operate. Depending on the voltage involved, this could be dangerous at best. Most appliances work off 110v or 220v, depending where you are in the world (the U.S. uses 110v, while here in the P.I. it is 220v). I will mention that it is not voltage that has the ability to kill you, it is amperage, or amps. If both are high, then your chances of getting hurt increase. If you do not have an understanding of that right at the start, you are in for a shock; literally! Many people get shocked by playing with stuff they don't understand (maybe you). Fooling with wall outlets, refrigerators, etc... can get you hurt if you don't understand electricity and how it flows. For some of you with training, you know all the things I am saying, and am going to say. This is designed a bit more towards the "home electronics or electrical expert"; (sarcastic). Many people will absolutely never try to wire a house themselves, because they understand that they do not have the expertise to do it. You most certainly will not string electrical high wire onto the telephone poles, because you know that it has the ability to kill you. They leave these things to the professionals, as they should.
Electrical current, or electricity, needs a path to flow through. It will take the path of least resistance. Circuits are designed knowing this. When they "make paths" for the current, they are building it to "force the flow" through where they want it to go, and away from things that need to be protected from electric current. An simple example of this would be; you see two wires that are not touching each other, so you decide to put them together. If there is electricity, or current, existing on the wires, you have just completed a path. If it is live, and you touch these wires, then get ready for the shock. What if you grabbed one wire in your left hand, and the other in your right hand. You have again completed a ciccuit path for the current; the problem is that it will be "through you!". Depending on the amps involved, you can received a mild shock, all the way up the ladder to death. What if you exposed wires, or took the insulation off without meaning to. Would you know if these wires are live? How could you tell? Would you touch them quickly to see? You better not! Depending on the amps again, just getting close to the wires could cause an arc that would throw you across the room. You need to get the proper test equipment (volt meter) and check it. If you are in a electronics or electrical field, you already know these are basic things. If you are not trained in one of these fields, then you may be asking for a real quick trip to heaven.
Appliances of a larger size that use compressors obviously carry more electricity and power. Even their wiring is different. Common sense would dictate that the bigger the wire, the more power it is carrying. The size of the wire used is called gauge. Just like a shotgun, the gauge of the wire tells the electrician what power he is dealing with. If you notice, you will see that high power line techs dress and wear very particulaar gear.  It is designed to try and prevent arcing, or making a path for the electricity. In other words, you want to insulate yourself.
The next thing is grounding. Grounding is vital.  Your house has a main ground to protect you. It gives the electricity a path to follow directly to the ground, the least resistant path. High towers, buildings, etc, especially the ones made of steel (almost all of them) have grounds. Usually it is a steel rod or pole put into the ground. Then a heavy cable or attachment is made from the pole to the building (it must have a good contact with the steel). If the tower is hit by lightning, and it is not grounded, then electrical flow could go anywhere; to a nearby structure, to a car, to you!. If it is properly grounded the "lightning" will travel throught the cable, to the ground, as designed. If you are in an office building, full of computers, or electrical equipment, and your building is not propering grounded, the electricity can follow the path of least resistance straight to your computers, blowing them up, I'm sure.
In the electronics world of circuit cards, push and pull asssemblies, and communications devices, the principles are no different.  There are steps taken to insure these components are protected from current flow. Even the slightest amount of current could "burn out" a circuit card. They are not cheap to replace, so the tech has to be trained on proper handling techniques. Many have to go through six months to years of training, depending on the scope of what they're working on entails. I'm just trying to pass on a few ideas on why you should either trained to work on equipment,, or whether you should leave the job to someone that is. Don't get electrocuted! On the next page, I will continue with a bit more, but to a more advanced level.