HDABOB's Tech Notes:

Do you ever wonder how the electrical system works?

Let me explain it to you...

The components of the electrical system consist of:





Ignition Switch




ECU (electronic control unit)

 The electrical system is what makes everything work!

Battery voltage from a fully charged battery is distributed throughout the vehicle by way of wires. These wires vary in thickness and composition. The heaviest wiring is devoted to the starter system. The Starter uses more amperage than any other component in the car.  The battery voltage is supplied to the starter through fuses when the ignition switch is turned to the start position. After cranking for approximately 3-5 seconds, the engine starts. After the RPM stabilizes, the alternator charges the battery at approximately 13.5 volts. The power is also distributed to other components such as the lights, A/C system, Radio, etc.

The supply of voltage to the ECU is reduced to 5 volts DC. The Electronic Control Unit is merely a computer, similar to the one you have at home, that monitors all systems on the car.  Whenever a discrepancy is detected, the self diagnosis function in the ECU determines which component is malfunctioning and isolates that component from the system. At the same time the ECU inputs a signal in place of that component so that the car will still function. At the same time, it turns on the engine check light to signal the driver that something has malfunctioned in the system. A diagnostic computer will tell the technician which component has malfunctioned and reset the ECU after repairs have been performed.

The alternator is a device that converts mechanical energy into electrical energy. A belt drives a rotating mass called the rotor inside the alternator that is surrounded by coils of wire and magnets. As the rotor rotates it induces a voltage of about 110 volts AC. A voltage regulator built into the alternator changes the voltage to about 13.5 volts DC and regulates that electrical current to the battery. From the battery, current is distributed to all electrical components in the car through various fuses. A fuse is a small length of wire inside a plastic case that will melt if the electrical current load exceeds a certain preset value, thereby protecting that component.

The starter is a device to convert electrical energy to mechanical energy. Voltage is supplied to a coil on the starter motor through the ignition switch. This motor is positioned on the engine near the flywheel. A gear engages the teeth on the flywheel, rotating the engine. After the engine is running the starter is disengaged. Hybrid vehicles have no need for a starter. The  hybrid motor that supplies power to the engine is used to start the engine. A hybrid vehicle uses power from a separate battery to power the hybrid electric motor. This battery pack is configured to produce approximately 144 volts DC to the electric motor between the engine and the transmission. When the car is accelerated, the power pack is used to help power the car up to speed. When cruising speed is reached, or engine breaking is being used to slow the car down,  the motor between the engine and transmission becomes a generator, recharging the battery pack.

The wiring is routed throughout the vehicle. It is usually hidden from view to protect it from harm. The wiring consists of various types of metal conductors and terminals. Some systems are more critical  than others, so this wiring is coated with gold, such as the airbag system, to insure continuous contact, free of corrosion. The body of the car is the path to ground for all the circuits. The wiring is so durable and insulated from external factors, that you can spray the engine compartment with water and not harm any circuits.

 On year 2000 and newer vehicles, the wiring acts as a communication medium for the various computers in the car. When the car is turned off, the computers communicate for a short time to ensure all circuits are functioning properly, then the computers nearly shut down. Any touch will "wake up" the computers again.

The gauges function to keep the driver aware of conditions surrounding the vehicle. The speedometer is driven by a speed pulser in the transmission. The tachometer is driven by the ignition system. The various gauges have sensors on and around the engine to keep the driver informed at all times. 

The maintenance reminder has evolved. Starting from the 04 Acura and 06 Honda, the maintenance reminder has been designed to give a little more information. The maintenance reminder system keeps tabs on conditions that require a needed service. Through a series of sensors and information stored in the Electronic Control Module, the maintenance minder looks at such variables as driving habits, elapsed mileage, and environment to determine the best time to perform maintenance, showing the information on the dash display. The indicator now shows percentage of oil usage left in the engine.  The system automatically moves up maintenance reminders to coincide with other services. For instance, if a tire rotation is scheduled for 7500 miles and an oil change is due at 9000 miles, the system will delay the tire rotation and move up the oil change to 8300 miles. Oil changes, and related services may come sooner or later depending on the customers driving habits. An engine running at freeway speeds or stop and go driving changes the maintenance requirements and therefore indicated maintenance.

...and that's the way the electrical system works!!

Now, for another humorous opinion:

The Smoke Theory of Electric Circuits
Electrical Theory by Joseph Lucas

Positive ground depends upon proper circuit functioning, the transmission of negative ions by retention of the visible spectral manifestation known as "smoke". Smoke is the thing that makes electrical circuits work; we know this to be true because every time one lets the smoke out of the electrical system, it stops working. This can be verified repeatedly through empirical testing.

When, for example, the smoke escapes from an electrical component (i.e., say, a Lucas voltage regulator), it will be observed that the component stops working. The function of the wire harness is to carry the smoke from one device to another; when the wire harness "springs a leak", and lets all the smoke out of the system, nothing works afterwards. Starter motors were frowned upon in British Automobiles for some time, largely because they consume large quantities of smoke, requiring very large wires.

It has been noted that Lucas components are possibly more prone to electrical leakage than Bosch or generic Japanese electrics. Experts point out that this is because Lucas is British and all things British leak. British engines leak oil, shock absorbers, hydraulic forks and disk brakes leak fluid, British tires leak air and the British defense establishment leaks secrets...so, naturally, British electrics leak smoke.

Subject: SMOKE

When wires smoke, how come the smoke is not the same color as the wire?

This is not completely true. When the smoke is in the wire, it is under pressure (called voltage). The pressure difference causes the color to change from the normal color we are used to. Not unlike the blood in our veins and arteries changing color due to the oxygen content. When the smoke escapes the wire and is exposed to air, the pressure is released, and the color reverts back to what we commonly recognize as smoke. The wire then changes to the color of the smoke that escaped.

I hope this helps you understand.

I would only question the last sentence of that description. It has been my experience that the wire turns a color directly opposite of the smoke.

Not always true, I think it must depend on the composition of the smoke in question.

I should have made it a little clearer; the color the wire becomes, is directly proportional to the escape velocity of the smoke. Higher velocities generate higher heat. This heat tends to burn the wire and affect the coloring. The statement was meant to be a generalization, indicating the fact that the color of the wire does in fact change. Sorry for the miscommunication.

I was speaking of electrical smoke which is generally white. The spent smoke casing generally assumes a color somewhat near black after the smoke leaves.

I can't stand it anymore! If, as you say, light bulbs suck up darkness and convert it to smoke which is transmitted (via wire) to a power source for recycling...why do car batteries go dead when lights are left on? Do car batteries (and flashlight batteries for that matter) have a limited amount of storage capability? Is it like a hard drive that gets so full that you have to double-space and then lose all data?

Now you're getting it.......

I thought you guys were smarter than this. Of course the battery stores the smoke. In fact it can store so much smoke that if you open the top and light a match, the resulting explosion can do serious damage. I'm sure you are aware that usually where there's smoke there's fire. If you connect the battery to a charger, the smoke is then returned to the wire (Remember, a light bulb wont work unless it is connected to a wire system) for the utility companies to use. Your hard drive analogy is a very good example.

Our hardware guys might be onto something in their quest for superior wiring. I have noticed the unique method of series/parallel wiring the power strips on our systems seems to prevent the smoke from getting out of the wires. A "Smoke Loop" of sorts. In the case of the "smoked" workstation recently, you should notice that this was a conventional single power strip installation.

Since color is perceived by the cone shaped receptors in our eyes, and cones require more light that their rod shaped counterparts. Is the sky blue at night?

At night the process including contraction of the pupil is visual purple by which the eye adapts to conditions of increased illumination when facing 300 candle power redeflecting devices.

Since there is a spectrum of light that we as humans cannot see, I support the theory that everything is going up in smoke, we just can't see it. This may explain why the neighbors dog barks for no apparent reason.

I think your basic understanding of smoke systems is remarkable. However I find a flaw with your theory. The battery is a reusable storage device for smoke. therefore, one would assume that some sort of one way valve (we can call it a diode) should be needed to prevent pressure flooding back into the system while at rest. Unlike the A/C system, the smoke system is collecting darkness at the headlights and converting it to smoke. This causes the system to fill up. The battery can contain much higher pressures and volumes than the wires. If this pressure exceeds the capacity of the wire, it will cause a rupture as you described. The rupture can be controlled by a sacrificial device known as a fuse. But this still doesn't eliminate the problem. Perhaps a two way valve (zener diode) is used to allow a small amount of pressure to return to the system, and partially equalize. I find this theory unlikely though, due to the increase in the force required to start the pump (which is now under pressure) working again...

The smoke continues circulating through the system, due to the pressure differential in the battery (smoke pressure/vacuum reservoir). When the reservoir becomes depleted, the pressure simply equalizes everywhere in the system (similar to an A/C system when it's turned off) and stuff just wont work. Notice the relations: Work (W) = Force (F) x Distance (D); Force (F) = total difference in pressure (Dp) x Area (A). Therefore, the work done in a pressure system is: Dp x A x D. If the pressure differential (Dp) is reduced to zero then W = 0 x A x D = 0.

The smoke only escapes the wires when a path is created between the pressure differential areas (@ either the reservoir or the pump) that has too little restriction. When this happens, the smoke travels through the wires so fast that the friction between the smoke and the outer walls of the wiring heats the wires until they rupture. The smoke continues to escape until its pressure is equalized with the atmosphere, or until the conduit that provides the path between pressure areas is severed. When this happens, the sudden drop in pressure allows the wires to "collapse" slightly and, being so hot, as the edges of the ruptures and severed ends touch, the material becomes fused, sealing the system and retaining the remaining smoke.

Don't forget, when the system is at rest, all the valves, (switches and relays) are closed, keeping the pressure areas separated. When restarting the pump, as long as everything is OK, the smoke pressure is equal on both sides of the pump and there is no net force on the pump when it begins operating again. Also, within the pump there are pressure/volume actuated one-way valves with restrictors built in, arranged in such a way that they keep excess smoke volume recirculating through an integral smoke loop, which maintains the pressure within manageable limits.

The excess smoke, created by the light/smoke converters (headlights and other darkness absorbing devices), is changed back to darkness and dissipated in small unit concentrations so its dark effect is not locally observed. The smoke pump impeller (stator), converts smoke into magnetic flux which does work on the engine. Some of the excess work energy is dissipated through the cooling system and exhaust in the form of heat, while the remaining work energy is converted back to smoke and distributed evenly in small concentrations as you drive. This maintains the total quantity of smoke in the system at an average that does not change over time.


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HDABOB's Mobile Service 09/15/2007