Analog and Digital Meters

Analog and Digital Meters Points :Definition, analog and digital meters, electronics instruments Meters can be classified not only by the parameter that they measure, but also by the type of display or readout used. Meter displays fall into two categories.
i. Analog
ii. Digital i. Analog Meter Analog meters generally use some sort of electromechanical mechanism to cause a small arm to move, depending on the Voltage or current applied to the meter. A graduate measurement scale is imprinted behind the mechanism such that the moving arm points to the Value of the meter reading. The actual mechanism involved is not critical; the important point is the analog meters provide a continuously varying readout, Without any discrete jumps in meter reading. The mechanism does not have to be mechanical. It can be implemented using other technologies as long as the result is a continuous “analog” type of display. Analog meters require care in observing meter readings. Different people Watching the same measurement may disagree slightly on the correct interpretation of the meter reading. The resolution of the meter (the ability to measure small changes) will depend on the physical layout of the meter, but generally will be no smaller than a few percent of the full-scale meter reading. The biggest advantage that analog meters have when compared to digital meters is the ability to track changes in meter readings. ii. Digital Meters Digital meters, on the other hand, do not provide continuously Variable meter readings. The meter reading is converted into decimal digits and is displayed as a number. This results in a reading that is very easy to interpret Several different people Viewing the same meter will usually record the same reading (except for cases where the number is changing due to electrical noise or measurement drift). Digital meters are usually specified according to the number of digits in the display. A- 3 ½- digit Voltmeter has three digit in its display. A 3 ½ digit voltmeter has normal decimal digits plus a leading digit which can have only the value I or 0 (the maximum reading for this type of display would be 1999). Digital meters lend themselves nicely to interfacing to computers, since both use digital numbers internally.

Adjusting a circuit for maximum voltage is much more difficult with a digital meter. The user must read the number, decide whether the new reading is larger or smaller than the previous reading, and then tweak the adjustment in the prover direction. For meters with three or four digits, this can be difficult. Some digital have included a simple analog like display in additions to the high resolution digital display to provide the best of both technologies. The digital readout can be used for precise absolute measurements while the analog display can be use to adjust for maximum or minimum value. Do not assume that the presence of many display digits automatically means very high accuracy. The digital meters work on the principle of quantization. These indicate the value to be measured in be from of a decimal number.