Electronics Basics

Based on many conversations I’ve had with people over the years, I’ve come to the conclusion that, of all the elements that go into a car, electricity is, by a wide margin, the most misunderstood. And not just by the layman, either. Electricity is a hang up for technicians and engineers, as well. I've also concluded that a great deal of this misunderstanding stems from the fact that electricity is invisible and formless, so its nature can be perceived only indirectly. Another reason for the misunderstanding is that electricity is not often taught well in many schools, possibly because the instructors don’t fully understand it, either. In the following section, I portray electricity as a phenomenon — which it certainly is — that can be reckoned with and worked with. So, what is electricity? What is this force that sparks the sparkplugs and lights the lights? Is it some kind of magic that only an engineer or scientist can understand? No! Webster’s New Collegiate Dictionary puts it like this: "Electricity is a fundamental entity of nature consisting of positive and negative kinds... usually utilized in the form of electrical currents." Mysterious, maybe, but not magic. Let’s try to improve on Webster: Electricity has positive and negative charges. It is an invisible force. It can be controlled. It can do work. It can flow in a current from place to place. It can flow only in a completed circuit. It can be "stored” in a battery. Pic. When the like poles (+ + or - -) of two magnets are close to each other, they repel. The unlike poles (+ and -) attract each other. This phenomenon is the basic key to understanding how electricity works. Positive & Negative — In grade-school science, you probably learned that magnets are electrical in nature, with a north pole and a south pole. On some magnets, north is marked + (positive) and south is marked - (negative). Put two magnets close to each other and you’ll see that like poles ( + + or - -) repel each other and unlike poles ( + — ) attract each other. This separation into positives and negatives is called polarity. It is the first important point about electricity, which will become clearer later. For now, just remember positive, negative, and the attraction between them. The Invisible Force — You can’t see electricity because it operates at an atomic level. All matter is composed of atoms. They’re so...

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An overview of the electrical system

Someone once said a car needs only two things to run — fuel and electricity. Well, OK, three things, if you count air. But the point is this: A car depends on only these three things for basic operation. “How can that be?” you ask. "Today’s cars are so complicated." Well, compare an old car with a modern one. If you look beyond the obvious, what do you find? The basics are the same. Nowadays, it’s only the application that’s more complicated. Take electricity. The essential electrical components in old cars and new ones are practically the same — ignition, starter, generator, battery and lights. But today’s cars also come equipped with electric wipers, electric gauges, electric windows — even electric mirrors. Most of today’s extras are just that — extras. But all these components have one thing in common. They all need electricity to operate. So, before getting into the specifics of electrical theory and how to wire your car, let's take a brief overview of the car’s electrical system. Brief overview of the car’s electrical system The electrical system can be divided into three major parts: electrical sources electrical loads — users of electricity electrical paths Electrical sources consist of the battery, which stores electricity for starting the engine, and the generator or alternator, which provides electricity when the engine is running. Except in cases of extreme overload, a correctly adjusted charging system will produce enough power to operate all the electrical devices in the car, with enough extra to recharge the battery. Electrical loads include all the devices on the car that require electricity for operation. Some examples are the ignition system, windshield-wiper motor, heater-blower motor, horn, radio or tape deck, and lights. By the way, don’t underestimate the electrical loads created by lights. It’s common for a car to have more lights than all the other loads combined — 20 to 30 lights can be found in a modern car. And, in some race-car applications, such as rally cars, off-road racers, and IMSA GTO and GTP cars, the electrical load from driving lights can be quadruple that of conventional lighting systems. Electrical paths include wires, of course. But a car's steel body and frame are also paths. They're used as the return path, or ground, between loads and the battery. And the various switches in the system can be included in the path category. Switches are located in the electrical path to act as a sort of...

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The Role of Electricity in the automobile

Electricity in the automobile
In the past, electrical systems were basically stand-alone. For example, the ignition system was only responsible for supplying the voltage needed to fire the spark plugs. Ignition timing was controlled by vacuum and mechanical advance systems. Today there are very few electrical systems that are still independent. Today, most manufactures network their electrical systems together through computers. This means that information gathered by one system can be used by another. The result may be that a faulty component may cause several symptoms. Consider the following example. The wiper system can interact with the headlight system to turn on the headlights whenever the wipers are turned on. Hie wipers can interact with the vehicle speed sensor to provide for speed-sensitive wiper operation. The speed sensor may provide information to the antilock brake module. The antilock brake module can then share this information with the transmission control module, and the instrument cluster can receive vehicle speed information to operate the speedometer. If the vehicle speed sensor should fail, this could result in no antilock brake operation and a warning light turned on in the dash. But it could also result in the speedometer not functioning, the transmission not shifting, and the wipers not operating properly.

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Why Become an Electrical System Technician?

Electrical System Technician
In the past it was possible for technicians to work their entire careers and be able to almost completely avoid the vehicle's electrical systems. They would specialize in engines, steering/suspension, or brakes. Today there is not a system on the vehicle that is immune to the role of electrical circuits. Engine controls, electronic suspension systems, and antilock brakes are common on today's vehicles. Even electrical systems that were once thought of as being simple have evolved to computer controls. Headlights are now pulse-width modulated using highside drivers and will automatically brighten and dim based on the light intensity of oncoming traffic. Today's vehicles are equipped with twenty or more computers, laser-guided cruise control, sonar park assist, infrared climate control, fiber optics, and radio frequency transponders and decoders. Simple systems have become more computer reliant. For example, the horn circuit on the 2008 Chrysler 300C involves three separate control modules to function. Even the tires have computers involved, with the addition of tire pressure monitoring systems! Today's technician must possess a full and complete electrical background to be able to succeed. The future will provide great opportunities for those technicians who have prepared themselves properly.

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