Electrical Engineering ⇒ Topic : Characteristics of Electrostatic Voltmeters
Characteristics of Electrostatic Voltmeters
It is worthwhile to mention the advantages, disadvantages and applications of electrostatic voltmeters.
(1) They can be used for both d.c. and a.c. measurements.
(2) They draw *negligible power from the mains. Hence such voltmeters do not alter the condition of the circuit to which they are connected.
(3) They are free from hysteresis and eddy cun-ent losses as no iron is used in their construction.
(4) Their readings are independent of waveform and frequency.
(5) They are unaffected by stray magnetic fields, although electrostatic fields (set up for instance, by such a simple process as rubbing the glass of the case to clean it) may cause considerable errors.
(1) The operating force is very small for low voltages so that they are particularly suitable for the measurement of high voltages.
(2) Since the operating force is generally small, errors due to friction are difficult to avoid.
(3) They are expensive, large in size and are not robust in construction.
(4) Their scale is non-uniform ; being crowded in the beginning of the scale
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