Find out how an analog meter can fix appliances and wiring problems.
An analog meter, which may also be called a volt-ohm meter or VOM, is a tool for testing electronic devices and electrical wiring. When an analog meter is connected, it becomes part of a circuit and displays information that can help to determine whether there is a poor or broken electrical connection, a lack of power or a nonfunctioning part. An analog meter might look intimidating, with all of its dials, numbers and switches, but learning how to use it is not as difficult as it appears. The knowledge provided by an analog meter is invaluable for individuals who wish to repair appliances or diagnose problematic wiring configurations.
A Massachusetts Institute of Technology professor explains that an analog multimeter measures the torque on a coil of wire in a magnetic field as an electrical current goes through the coil. The device is called a multimeter because, with a simple flick of the range selector switch, it can change from measuring resistances to voltages and back again. Analog meters measure direct current, alternating current voltages and resistance. Digital multimeters can provide far greater decimal precision, but they are not as easy to use.
Before using an analog multimeter, one must decide whether to test for current, ohms or voltage. Then a range for testing is selected. The function switch must be set properly in order to avoid overloading and damaging the multimeter. When testing a 120-volt outlet, for example, a setting of 120 volts or higher is needed to prevent overloading.
A multimeter has two metal-tipped testing probes connected to jacks in the meter. When testing a direct current, the red probe must be connected to the positive meter jack and the black probe to the negative. Once both probes are connected, the meter will move proportionally to the current that is flowing through it. A zero reading means a closed circuit has been achieved. The needle on the meter moves to the far right when this occurs. The needle remains on the far left side of the dial if the circuit is open.
The Family Handyman notes that when using an analog meter, it can be tricky to know which is the correct scale on the dial. The reading may have to be multiplied by 10 or 100 to obtain the final value.
Analog multimeter users are advised to read the owner's manuals carefully, follow recommendations and heed all warnings within in order to ensure their safety and prolong the life of their analog meter.
Home improvement, electronic or hardware stores sell analog meters, and they are also available for purchase online. Prices for analog meters begin at about $15. Higher prices generally indicate greater precision. Prior to purchasing, the consumer should consider how much precision is required based on the analog meter's intended use.