Multimeter

By Author: Jamie Hanson
Total Articles: 3534
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If you remember the last time you faced a problem with your air-conditioner or your television and you called up an engineer to check your appliance. He would always come up with a black colored box with two red and black wires (also called as probes) and touch them at various parts and IC's of your television and note down something from that box. Well that black colored box is nothing else but a multimeter. A multimeter being a hand-held device is used for finding out the basic faults by lessening the area of fault as well as the field service work or a bench instrument which is able to measure with a very high degree of accuracy. Since they have a high accuracy thus they are used to trouble shoot electrical faults on a large scale of industrial, household devices like batteries, motor, electrical appliances and wiring systems. A multimeter is an electronic measuring instrument that can measure voltage in volts, current in amperes and resistance in ohms ,also known as VOLT/OHM meter or a VOM . Apart from
these three it can also measure capacitance in farads, frequency in hertz, and temperature in degrees Celsius or ...
... Fahrenheit. And it is because of this reason only that it is given the name multimeter i.e. multiple meters. You can make your multimeter as complex as you wish and add as many features as you want but take care of the cost, the more the number of features the more the cost.

The two main kinds of a multimeter are analog and digital. A digital multimeter comes with an inbuilt LCD screen that gives out the exact decimal readings, on the other hand an analog display moves a bar through a range of numbers and it has to be interpreted to get a proper reading. Any multimeter will work over a specific range for each measurement. Select one that's compatible with what you meter most, from power sources of low-voltage to car batteries with high-voltages Multimeters are very specific as they are provided with a sensitivity range, so make sure you get the appropriate one.

Now that we are familiar with what multimeters are we should even acquaint ourselves with its working and other features. The internal circuits of analog and digital are quite different but working with both of them is almost same. If your multimeter is new make sure you install batteries before using it. Now follow these simple steps:
1. Turn the meter on and insert the probes into the correct connections - this is required because there may be a number of different connections that can be used. Be sure to get the right connections, and instead of putting those in a low current a high voltage measurement is done it will damage the multimeter.
2. Not put them into the ones for a low current measurement if a high voltage measurement is to be made - this could damage the multimeter.
3. Set switch to the correct measurement type and range for the measurement to be made. When selecting the range, ensure that the maximum for the particular range chosen is above that anticipated. The range is very important although it can be reduced later a high range prevents it from getting overloaded and reduces any damage caused by movement of the meter itself.
4. Optimize the range for the best reading. If possible enable all the leading digits to not read zero, and in this way the greatest number of significant digits can be read (in case of digital multimeter). In case of analog multimeter adjust it so that the maximum deflection of the meter can be gained. In this way the most accurate reading will be gained.
5. After the reading are taken, it is better to put the probes in the voltage measuring sockets and increase the voltage to full . This indirectly prevents the meter from damage even if the meter remains accidentally connected forth range used.

For safety reasons, you must NEVER connect a multimeter to the mains supply.