Knowing a bit about basic electricity can come in very handy for the videographer or photographer!!
You deal with basic electricity all the time! Your video camera, any type of lighting gear that you use whether it be flash, strobe or stage lighting and even your video editing computer, of course, runs on electricity.
Since you use electronics and electricity all the time you will run into basic electricity and battery terms frequently. Having a good working knowledge of these terms will make it easy for you to efficiently operate your equipment, troubleshoot it when need be and... Help you understand (especially when buying replacement batteries or lighting equipment) what the specifications mean and which battery or piece of equipment is best for you and your video production.
Here are the definitions of some of the most common terms of basic electricity.
This may be the most used term in basic electricity. Voltage is the potential energy, sometimes called electromotive force, that makes the electrical current (made up of electrons) to flow through a conductor in an electrical circuit.
When were talking about voltage were talking about "pressure" or potential force.
Voltage is measured in units called Volts and is shown as a "V" in specifications and schematics. If you can't visualize this… Here's an analogy that may help you to better understand what voltage is. Let's use a water-in-pipes analogy. In this analogy the electrical conductor (wires, printed circuit board etc.) = the water pipes. Volts = the water pressure.
The higher the pressure in the water pipes the more water is delivered. The same is true for electricity moving through an electrical conductor. The higher the voltage (pressure) the more energy (or current flow) is delivered to the electrical or electronic device or power outlet.
For you science majors out there... The more precise definition is that a volt is a unit of electrical potential difference across a conductor when a current flow of one Ampere dissipates one Watt of power.
(Note: Watts is a measurement of the amount of electricity being used (the rate of consumption) by an electrical device).The mathematical formula to figure out voltage (just in case you're interested) is: Volts = Watts divided by Amps.
Is a unit of measurement used in calculating the rate of total electron flow (or current flow) through an electrical conductor.
Let's stick with our water-in-the-pipes analogy that we used for voltage and extend that to amps. In the water pipes the total flow could be measured in let's say… Gallons Per Minute. The more you open the water spigot (increasing the water pressure) the more waterflow you get.
It's the same idea with current flow in an electrical circuit. Amps tell you the amount of electrical flow there is in the circuit. Now… If we want to take this one step further we see that the higher the voltage (pressure) the more potential flow there is.
There are good reasons why you should always know what the correct voltage is for your electrical devices. Using a battery or plugging into a power source with too high of voltage will increase the volume of current flow… Sometimes dangerously past the capability of the device that is using the power.
This usually ends up in overheating the device and often times will damage or destroy it. As you know… Digital cameras, flash units or lighting units are expensive and you don't want to have to replace them or worse yet have them overheat or explode causing fire or damage.
:A type of electrical current that reverses direction (plus, minus, plus, minus... etc.) periodically.
An Ampere hour (sometimes abbreviated Amp hour) is the amount of energy (charge) in a battery that will allow one ampere of current to flow for one hour.
Ampere hours tell you the capacity of your battery and how long it will last before it has to be recharged.
A device that can store electrical power (in chemical cells or my other means) and then produce this electrical power for use on demand.
Once the battery power has been depleted it can be recharged and used over and over again.
In basic electricity, this refers to any type of material that allows the free flow of electrons.
Some conductors are better than others. For example, gold, silver and copper are the best conductors (in that order). You'll see this advertised a lot with companies that make audio and visual products. Gold and silver are, of course, of the highest quality (and most expense) and will give you the most efficient current flow to your device.
The volume of the movement of electrons through a conductor is measured in Amps.
This type of electrical current only flows in one direction. This is the type of current that is used in portable digital devices and is created by the digital devices battery.
In basic electricity, this term is... the flow of electrons through a conductive material. The unit of measurement for electrical current flow is the ampere.
For example when you're looking for replacement camera batteries you will see this listed as one of the specifications usually in milliamps.
The capacity to exert electrical "pressure" .
"Potential" means that it is not necessarily exerted but... present to be used. It is measured in Volts.
This is a term not well understood by most people. In basic electricity the definition of Ground is that it provides a normal path for electricity to flow. There are two types of ground: Earth Ground and Floating Ground:
Earth ground is when the circuit has a physical connection to the earth. This type of ground is present when you plug your electrical device into a wall outlet. It serves as a path for the electricity to flow and also as a safety factor when using high-voltage devices. A floating ground also called a "virtual ground" is not directly connected to the Earth. Battery's have floating grounds. In batteries the floating ground serves as a type of 0 V reference line that serves as return path for current back to the negative side of the battery.
The load in an electrical circuit is what is being powered. For example: the battery in your camera is powering the electronic components of the camera... they are the "load". In stage lighting the "load" would be the lamp. You get the idea.
I've included this term in the basic electricity definitions as you run into it, especially, when you're shopping for batteries. A microcontroller (sometimes abbreviated uC or MCU) is a small "computer" on a single integrated circuit board containing a processor, memory and programmable input/output peripherals.
It is normally used to control some function in your electrical and/or digital equipment or device.
Milliamp hour is an important basic electricity term as it is the easiest way to distinguish the capacity of a battery for a digital device. The higher the milliamp hour, the longer the battery will last.
Batteries with a different milliamp hour ratings are interchangeable however. If your batteries rechargeable then the milliamp hour rating is how long the battery will last per charge. The milliamp hour is 1/1000th of and amp hour.
Example: 1000 mAh = 1.0 Ah. To better illustrate this let's use the analogy of the gas you use to power your car. The milliamps (the measure of current flow) are how much gas is being used. Milliamp hours is the size of the gas tank. The bigger the gas tank the longer your car can run... Right? And so it is with an electrical device using a battery with a high milliamp hour rating. And just to carry on a little further with this analogy… Once your battery is used all its power... then its refillable by recharging it… Just like a gas tank is refillable once you've used all the gas!
The main thing to remember about this for the videographer or photographer is that… The more milliamp hours a battery is rated for the longer your device will have power before recharging.
In basic electricity... "Nominal" just means that the actual voltage may vary a bit.
You'll see this listed sometimes on the specifications for batteries, video cameras or camcorders or lighting equipment. Almost all electronic equipment is built so that it can operate even though the voltage varies a bit. There are always small fluctuations in voltage whether your device is powered by batteries or if you plug into a wall outlet.
This term basically refers to the resistance to current flow between two terminals. How easily does the electrical current flow through the conductor (whatever material that might be) to its destination. I've included this in the basic electricity terms as you'll see this every once in a while on your equipment.
This would be where your electrical power comes from. For smaller cameras that is almost exclusively a battery or battery pack. For the more expensive cameras you normally have a choice of using a wall outlet for power or a very powerful battery pack.
For stage lighting it's almost exclusively wall outlet power as most lighting requires a tremendous amount of current for relatively long periods of time. For flash units... a battery pack is standard but there are some that can be plugged into a wall outlet also.
The ease or difficulty of electrical current to flow through a conductor is measured in Ohms. See the definition of ohms above.
A switch activates the electrical circuit (causes the electrons to flow through the circuit) and (keeps) the circuit active as long as the switch is in the "on" position.
So… Those are some of the most basic terms electricity that a videographer or photographer should know well!
Have fun...! Dan
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