# Electrical Measurements Questions and Answers – Autoranging

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Autoranging”.

1. Autoranging means __________
a) automatic ranging
b) fixed ranging
c) automobile ranging
d) constant ranging

Explanation: Autoranging refers to obtaining an automatic reading with optimum resolution under all operating conditions. Say for example, 155 mV is displayed as 155.0 and not 0.155.

2. A 3 digit display DVM with a maximum reading of 1999 indicates __________
a) increase by a factor
b) reduction by a factor
c) no change in value
d) depends on the circuit components

Explanation: A 3 digit display DVM with maximum reading capability indicates that any reading above the maximum set limit of 1999 will be reduced by a factor of 10.

3. For a value less than 0200, the instrument should ________
a) read values less than 0200 correctly
c) automatically switch range
d) should not respond at all

Explanation: The DVM should automatically switch its range when the display is greater than 1999 units as it is the maximum set limit for achieving a higher sensitivity.

a) attenuates the signal
b) converts digital to analog
c) converts analog to digital
d) contains information

Explanation: When the count produced by the ADC counter is less than 170, a control pulse is obtained for down ranging. Whereas the control pulse for up ranging is produced once the ADC counter exceeds 1999 units.

a) True
b) False

Explanation: ADC contains information required for polarity indication. The polarity of the signal that is integrated is of utmost importance.
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6. Integration period is obtained by ________
a) using signal amplitude
b) counting the pulse
c) measuring time
d) by differentiating the signal

Explanation: By counting the pulses we obtain the integration period. Polarity measurement is obtained by making use of the last count or some of the last counts.

7. Integrator’s output is ________
a) attenuated through a filter
b) feedback to the input
c) stored in a flip-flop
d) differentiated

Explanation: The output from the integrator is used to set a polarity flip-flop. The flip-flop’s output is then stored in memory until the next measurement of voltage is obtained.

8. Old information is used to set range relays.
a) True
b) False

Explanation: Range relays are set through the decoder using the new information obtained with the help of a clock pulse. Decimal point is also changed as per the requirement of the new range.

Sanfoundry Global Education & Learning Series – Electrical Measurements.