Insight - How Digital Multimeter Works
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As the name suggests, multimeters are those measuring instruments which can be used to calculate multiple circuit characteristics. Making them digital gives highly precise outputs as unlike their analog counterparts, there is no needle whose pointer is to be figured out. How are the digital meters more advanced than their predecessor? What internal circuitry is there to power such quick and rapid calculations? Just simply hook it to the circuit and take readings on the fly? Multimeter does that for us. So let us explore the Nitty Gritties of the Multimeter that make it a jack of many (if not all) trades of electrical measurements.
The image above depicts commonly used multimeter. Encased in a durable plastic casing, this measuring and testing instrument comes with an optional support to make it stand tilt for easy reading purposes.
Every multimeter comes with a few specifications that define the functions and range it can measure. For instance, the one in this insight can measure DC voltage in the range between 400mV to 1000V and resistance can be measured from 400Ohm to 400MegaOhm. Apart from measuring the conventional measurements of current, voltage and resistance, the instrument shown can also test logic, measure diode characteristics, and test transistor for small current gain and even measure frequency. To measure continuity, a buzzer is provided which makes a sound indicating the circuit is working.
Accuracy is one of the most critical aspects in the specifications. This degree of closeness of the measured result to the actual one should be as high as possible. Lesser the deviation margin, higher would be the accuracy. For instance, a multimeter measuring voltage with +/-0.6V accuracy would be more precise in its reading when compared to +/- 0.8V. Often quality of multimeters is judged on the basis of accuracy.