If you are a qualified electrician or a member of an allied trade/professional then don’t bother any further with this article. However if you are a non technical person who is occasionally baffled by electrical problems and their associated terms then the following may help you understand the basics of car electrics.

I also pay my respects to the anonymous author who first wrote the famous ditty on “Joseph Lucas - Prince of darkness - or why the poms drink warm beer” where to my knowledge the concept of electrical energy as smoke was first published..

As a 15 year old apprentice radio/radar technician I still remember how hard it was to come to grips with the concept of electrical energy. You can see it in lightning and sparks; feel it in an electrical shock; smell it in ozone; actually taste it by putting a 1.5 volt battery on your tongue [it tastes salty]; hear it in electrical spatter across insulators, bangs in thunderstorms and the zap of an electrical spark. But in the end you are still left wondering what it is, as all of the foregoing are actually secondary characteristics of electrical energy.

They used to attempt to teach us by using the concept of water storage and flow but this did not “gell” too well with we apprentices. However one enlightened instructor introduced us to the idea of “swarms of electrons” doing their thing and the concept stuck. It was very close to the concept I am about to expound which is simply to visualise these electrons as smoke.

I repeat if you wish to visualise electricity simply think of the electrons as smoke.

Volts refers to the pressure under which the smoke is produced and used. Amperes commonly shortened to amps. refers to the amount of flow of smoke being produced or used. Watts is an expression of the overall quantity of smoke being produced or used. [It is simply volts multiplied by amperes]. These are important concepts to grasp before you read on.

What the electrical components in your motor vehicle do

Alternator/Generator Produces the smoke typically under a pressure of 12 volts and a quantity set by the ampere rating. Generally the faster a generator spins the more smoke that can be produced. Alternators produce smoke by pumping in a trickle of smoke and which creates a spinning magnetic field and can produce smoke even at the idle Note that they can pull ½ and up to 1 horsepower from an engine.

Regulators Generally control the pressure of the smoke produced by the alternator/generator. It may also be able to limit the quantity of smoke produced by these items to stop them burning out.

Battery Stores the smoke at a certain pressure typically 12 volts. Its cold cranking storage [CCS] indicates it’s capacity to store and release the smoke. The bigger the number the more it will store and release.

Starter Motor Converts smoke into mechanical energy. It consumes lots of smoke very quickly to achieve this. Use it too long and it will consume all of the smoke in the battery.

Wiring Directs the smoke to various parts of the electrical system. The bigger the flow of smoke needed by an electrical part the thicker the wire. The thickest wire is normally the lead to the starter motor. Note that if the wire is too thin the friction from the flow of smoke may burn the wire.

Lights The smoke is fed through very fine tungsten wires in a vacuum creating friction which makes the wires glow white hot to produce light, There are lots of variations types including quartz halogen, krypton etc. but the principle remains the same. Note that your neon or fluorescent light at home works on an entirely different principle of smoke exciting special gases.

Resistors Used in electrical circuits to cut down the quantity of smoke and also the pressure. Commonly found in dashboard lights, variable speed air blowers in air-conditioning and the volume control of the car radio.

Condensers/capacitors Can make a short term storage of DC smoke but will allow the passage of AC smoke. A very important and usually neglected component in the spark ignition circuit.

Spark/ignition coils Transforms smoke from low pressure / high flow smoke to high pressure/ low flow smoke required to make a spark plug work. Note works by converting DC smoke into AC smoke

Spark plug Where the very high pressure smoke jumps a gap and ignites a petrol/air mixture in the engine cylinder. Resulting noise forms the exhaust note out of the tailpipe.

Ignition distributor Distributes the very high pressure smoke along special wires with very thick coatings of insulation [called ignition leads] to stop the smoke escaping to the engine and body of the car.

Switches Very simply starts and stops the flow of smoke by forming a cutoff or a closure in the wire along which the smoke flows.

Fuses Pieces of wire of a predetermined diameter in a glass tube or a plastic gizmo. Rated in amps[amperes] meaning how much smoke can flow before the fuse does it's job Due to the friction developed by the smoke flow the wire will melt if too much smoke is used. This stops the car wiring getting burnt out. Note circuit breakers do the same job but are much smarter. They detect the excessive flow of smoke and turn themselves off like a switch before the system burns out.

Electrical circuit For the smoke to flow there must be a complete circuit. This is often a difficult concept to grasp. It is best remembered that once the smoke particles have done their work they must be returned to the original source. In most motor vehicles this is done by earth return through the metal of the body of the car. Don’t forget that dirty or rusted earths and wire connections can be a major problem in the circuit of older cars.

AC/DC smoke [no we are not getting kinky] The majority of electrical devices in a motor car use DC [direct current] smoke. That is a steady pressure from a smoke source which is typically a battery or an alternator[or generator]. AC smoke is different in that it pushes from one end and then the other end of a circuit very quickly. It is not commonly used in vehicles except that the ignition system including the coil, condenser etc. converts the low pressure DC smoke into high pressure AC smoke that produces the spark for the spark plugs.

If you have managed to get this far you may have grasped some concepts of what car electrics are all about. As one family member remarked after watching a television documentary on major brain surgery “it looks very easy” and it is not that hard until you have to try and track a fault when it can become very difficult.

If you intend to do electrical work on your own car might I suggest you purchase a simple multi meter. Basically one with a needle commonly called “analogue” is best. The digital ones are very good but too complex and accurate for the average persons needs. Remember the pressure of the smoke is in volts, the flow of the smoke is in amperes and the quantity of smoke is in watts. Multiply volts by amperes to get watts. Eg 12 volts X 5 amps = 60 watts.

Xmas Wish List With Christmas just round the corner here are a few items that the Jaguar enthusiast might like to request from Santa. [you can always ask Santa for the impossible]

An SU fuel pump that never stops working

An XK engine that doesn't leak oil

Lucas electrics that never fail

A cooling system that never overheats

Leather seats that don't crack

A moss gearbox that changes quickly

Oil pressure that does not drop to near zero at idle

A Jaguar body that does not rust.

The editors tell me that this is the last issue for the year 2000. I would like to extend my compliments of the season to all of my loyal readers [ both of them!] and wish you happy and safe motoring in the forthcoming real millennium.