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Direct Current (DC)


The acronym, DC, stands for Direct Current. This is a completely different circuit than alternating current, because the power remains constant. In this portion of your journey you will be shown different ways of producing electricity, it's history, and the theory behind the formulas used by electricians and engineers on a daily basis.

You will hopefully at the end of this area, have a better idea of the magnitude of power that is being harnessed. Electricity is a phenomenon. The potential danger of incorrectly harnessed power can be devastating. That's why we're doing everything we can to show you the "safe" way to do your job.

Methods of Producing Electricity

Electrochemistry - Combining chemicals with certain metals causes a chemical reaction that transfers electrons.

Static electricity - When an object with a normally neutral charge loses electrons, due to friction, and comes in contact with another object having a normal charge, an electric charge is exerted between the two objects.

Magnetic induction - Rotating coils of wire through a stationary magnetic field or by rotating a magnetic field through a stationary coil of wire produces a potential.

Piezoelectric effect - Bending or twisting certain materials will cause electrons to drive out of orbit in the direction of the force. When the force is released, the electrons return to their original orbit.

Thermal -Thermoelectricity - Heating two joined dissimilar materials will cause a transfer of electrons between the materials setting up a current flow.

Light - Photoelectric effect - Dislodging of electrons from their orbits by light beams creates positively-charged objects.

Thermionic emission - Freeing electrons from a hot surface causes electrons to escape.

Magnetic being the most common, and widely used.

Matter and the Electrons (Hint - Electrons make Electricity)
If you're a genius you can click here to get a report on additional quantum theories. But, if you're like the rest of us...keep reading on.

Matter - is anything which has mass and takes up space.

Atom - The fundamental unit of matter made up of protons, neutrons, and electrons.

Electron - A negatively charged part of an atom that moves in the space around the nucleus

Neutron - A particle found in the nucleus of an atom that does not have an electrical charge

Proton - A particle found in the nucleus of an atom that has a positive electrical charge

Quark - Tiny particles that are components of protons and neutrons

Valence Shell - The outermost shell of an atom that can gain or lose electrons during chemical reactions.

First Orbit - No more than 2 electrons.

Second Orbit - No more than 8 electrons.

Third Orbit - No more than 18 electrons.

Fourth Orbit - No more than 32 electrons.

Ohm's Law - so VERY useful....

Don't get freaked out...just remember these rules and you'll be fine. Trust us.

Series Circuits
- Only have one path of current flow. The only thing that stays the same is current.

Formula for Current (Amps) ( I ) is... IT = I1=I2=I3 - Current stays the same

Formula for Voltage (Volts) (E or V) is... ET = E1+E2+E3 - Voltage adds.

Formula for Resistance (Ohms) (R) is... RT = R1+R2+R3 - Resistance adds.

Parallel Circuits - More than one path. The only thing that stays the same is voltage. And the resistance is a reciprocal, or divided by one.

Formula for Current (Amps) ( I ) is... IT = I1+I2+I3 - Current adds.

Formula for Voltage (Volts) (E or V) is... ET = E1=E2=E3 - Voltage stays the same.

Formula for Resistance (Ohms) (R) is... 1/RT = 1/R1+1/R2+1/R3 - Resistance is the reciprocal

Total power = Voltage (E) multiplied by Amps (I) ....or shorter... P=E X I

The following wheel is a combination of the most used formulas used in electrical today. In each quarter, there are three formulas to get a certain value. For instance, to get a result of Volts (E) - there are three formulas - R X I, P/I, and P X R squared. And so on. Feel free to copy and paste this wheel to your book. There are no copyrights. The one you should NEVER forget is P= E X I. Or another way of saying it is Watts = Volts X Amps.


Batteries - are considered direct current. DC, because they have a constant charge. They have a stored energy, that when connected to a path from negative to positive, it creates a difference of two points. Otherwise, it is called a potential difference. A bird sitting on a power line doesn't get electrocuted, but the minute (the second) it touches two lines at the same time - it goes to heaven. We don't want you to go to heaven. Turn the power off!

There are two types of batteries

Primary Batteries - Disposable. Throw away.Types include - Alkaline Cell, Aluminum/Air Cell, Leclanché Cell (Zinc Carbon or Dry Cell), Lithium Cell, Mercury Oxide Cell, and Zinc/Air Cell.

Secondary Batteries - Rechargeable. Reuse.Types include - Iron Nickel Cell, Lead/Acid Cell, Lithium Ion Cell, Nickel/Cadmium Cell, Nickel/Metal Hydride (NiMH) Cell, Nickel/Zinc Cell, Sodium/Sulfur Cell

For a more in depth look at batteries, maintenence, etc. Look in our Industrial or Solar section of this site.