Unless you live in the hollowed out portion of tree stump, you use electricity extensively. In fact, have you ever had the power go out for several hours at your home or work? It feels like an eternity before the lights finally turn back on. Just goes to show how much we are dependent on electricity. With all these electrons flying around and with the huge number of electronic devices we have, you will no doubt have a time when you could make great use of a multimeter.
Sounds like a fancy word, but really its a simple device designed to help you measure and test certain types of electricity. There are two types of electricity. AC or alternating current, and DC, direct current. Direct current is the type of electricity used in 6, 9, 12, + volt battery systems. Your iPod, car, boat, and electric nose hair trimmer use DC type current. Your desktop computer, big screen TV and electric lava lamp use AC or alternating current. Trusty multimeters help you test these types of circuits.
Now you might be thinking that only burly men that wear hard hats, and carry big belts with lots of tools on them would ever need to use a multimeter. Not true! If you have ever had a Christmas tree string of lights go out, you might have had use for a digital multimeter. If your blender suddenly stopped blending, you could test your outlet to see if current is still flowing. Perhaps your flashlight battery went out… is it the light bulb or the batteries?
In addition to these types of test situations, most multimeters also allow you to test for more sophisticated circuits and situations. You can test resistance of a circuit. This is the amount of friction introduced in the circuit by certain gauges of wire, or special electrical components called “resistors”. You can think of electricity like the flow of a type of invisible “water” or “electrons”. Just like in actual water systems, like canals, dikes and dams, electrical circuits have similar components that help guide the “flow” of the electricity. Some of these components slow down the “flow” of electricity, some “store” electricity (batteries and capacitors), some even step up the velocity of the flow or change it, like transformers.
In reality, a multimeter simply allows you to test the flow of these electrons. You can even test the “continuity” of an electrical circuit. This means you can test whether there are any “breaks” in the system. Lets take a flashlight as an example. There must be a continuous connection between the batteries, through the switch, and on through the lightbulb filament.
If any part of this “circle” is interrupted, then you loose a continuous connection. The “flow” of electrons is interrupted and therefore the light filament cannot be activated. The switch must be in the “on” position. The batteries must contain stored energy and be connected in a continuous circle through each battery, through the switch an on through the filament. If any part of this breaks down, you don’t have light.
Just like in a water system, if the canal has a leak somewhere, the flow of water will stop or weaken, and it can’t turn a paddle wheel. In order to fully understand a multimeter and it’s capabilities, it is first important to understand the basics of electricity.
I suggest that you purchase a very simple electronic kit and build some of the basic projects. Like an “LED” circuit, or a motion or light detector circuit. I guarantee that you will have hours of fun, and you will learn about the seeming magic that occurs around you every day.