What is a Multimeter?
A multimeter is also known as a VOM. It is an electronic measuring instrument which combines several measurement functions in one unit. This device can measure voltage, current, and resistance. There are analog multimeters also which use a micro ammeter with a moving pointer to display readings. Digital multimeters provide a numeric display, and also show a graphical bar which represents the measured value. These useful devices are now far more common because of their cost and precision. It can be a hand-held device which is useful for basic fault finding and field service work, or a bench instrument that can measure to a very high degree of accuracy. These devices can also be applicable to troubleshoot electrical problems in a wide range of industrial and household devices like electronic equipment, motor controls, power supplies, domestic appliances, and wiring systems. Multimeters are available in the market a wide range of features and prices as per the varied requirements of the customers.
Types of Multimeter
There are different types of multimeter like Analog, Digital and Fluke multimeters.
- Digital Multimeter: This is the most common type of multimeter which performs all functions from AC to DC other than analog. This device has two probes positive and negative. The Digital Multimeter basically comprises an LCD display, a knob to choose various ranges of the three electrical characteristics, an internal circuitry consisting of a signal conditioning circuitry, an analog to digital converter.
- Analog Multimeter: The analog multimeter is designed using a moving coil meter and a pointer for indicating the reading on the scale. The moving coil meter comprises a coil wound around a drum placed between two permanent magnets. As current flows through the coil, a magnetic field is induced in the coil that reacts with the magnetic field of the permanent magnets. The resultant force causes the pointer which is attached to the drum for deflecting on the scale, indicating the current reading.
- Fluke Multimeter: These devices are protected against the transient voltage. They automatically range to select most measurements.
Advantages of a Multimeter
Multimeters have high input impendence, so there is no loading effect. They have higher accuracy. With this device, an unambiguous reading is obtained. The output from this device can be interfaced with external equipment. These devices are available in smaller sizes and can be used for measurement of A.C. and D.C. both quantity. They can also be used for measurement of various parameters such as resistance, voltage, current etc. With a sensitivity of 20 kΩ/V, measurement of quantities with different range can be possible. Small in size and compact in design, it is very simple to use this device.
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