Electrical Measurements & Measuring Instruments Multiple Choice Questions on “Advantages of Electronic Instruments”.
1. Electronic voltmeters use electronic circuits.
a) True
b) False
Answer: a
Clarification: Voltmeters that make use of rectifiers, diodes, amplifiers, etc in order to produce a current that is in proportion to the quantity that is being measured is known as an electronic voltmeter.
2. In olden days voltmeters were __________
a) made of transistors
b) made of vaccum tubes
c) made of transformers
d) made of diodes
Answer: b
Clarification: Initially, voltmeters were made of vaccum tubes. These voltmeters were known as vaccum tube voltmeters (VTVM).
3. Modern day voltmeters are made of __________
a) made of transformers
b) made of vaccum tubes
c) made of transistors and diodes
d) made of insulated iron coils
Answer: c
Clarification: Nowadays in voltmeters, transistors and semiconductor diodes are used. A transistor voltmeter makes use of transistor in a voltmeter.
4. FETVM is __________
a) an ammeter
b) a galvanometer
c) a multimeter
d) a voltmeter
Answer: d
Clarification: Field effect transistors can also be used at the input. Such voltmeters are known as FETVM (Field Effect Voltmeter).
5. Electronic voltmeters are __________
a) compact
b) large in size
c) not portable
d) difficult to use
Answer: a
Clarification: When compared to conventional analog voltmeters, electronic voltmeters are compact and also portable. This is due to the small size of the components.
6. Electronic voltmeters are not accurate.
a) True
b) False
Answer: b
Clarification: Compared to analog voltmeters, electronic voltmeters are very accurate and precise.
7. Electronic voltmeters are __________
a) dependent of frequency
b) dependent of voltage
c) independent of frequency
d) dependent of current
Answer: c
Clarification: Usually electronic voltmeters can measure frequency in the range of a few volts D.C. to frequencies of the order of hundreds of MHz. As a result, the effect of frequency on the response of electronic voltmeters is negligible.
8. Dynamic range of electronic voltmeter is __________
a) zero
b) limited
c) narrow
d) wide
Answer: d
Clarification: When compared to conventional analog voltmeters, the dynamic range is very wide and improved in electronic voltmeters. Very low as well as very high input signals can be measured using an electronic voltmeter.
9. Loading effect in electronic voltmeters is __________
a) nil
b) high
c) low
d) medium
Answer: a
Clarification: In an electronic voltmeter as the power is supplied by an external circuit, there is no loading effect. In a PMMC instrument, a minimum current of 50 µA is obtained from the signal that is to be measured and this leads to loading effect.
10. Electronic voltmeters are ____________
a) measure high level signals
b) measure low level signals
c) measure medium level signals
d) don’t measure any signal
Answer: b
Clarification: Electronic voltmeters make use of amplifier circuits. As a result they can be used for measuring low level signals.
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