Unit 2 part 2

In a series-type ohmmeter

• zero marking is on the left-hand side

• zero marking is at the centre

• zero marking is on the right-hand side

• zero marking may be either on left or right-hand side

In series type ohmmeters, zero adjustment should be done by

• changing the series resistance

• changing the series and the shunt resistance

• changing the battery voltage

• changing the shunt resistance across the meter movement

Shunt-type ohmmeters have on their scale

• zero ohm marking on the right corresponding to zero current

• zero ohm marking on the right corresponding to full scale current

• infinite ohm marking on the right corresponding to zero current

• infinite ohm marking on the right corresponding to full scale current

Shunt-type ohmmeters have a switch along with the battery to

• disconnect the battery when not in use

• prevent meter from getting damaged when measuring very low resistances

• compensate for thermo-emf effects by reversing battery polarity

• all of the above

Short circuit, carries --------current and therefore resistance is minimum or zero

Open circuit ,gives maximum ---- and therefore resistance is maximum or infinity

The purpose of series resistor R₁ in series ohm meter is ------------

• current limiting resistor

• voltage controlling resistor

• none of the above

A 500 ohm basic meter is to be used as a series ohmmeter requiring a fsd of 1 mA and internal battery voltage of 5 V.A half deflection scale marking of 2 kΩ is desired. Calculate value of R₁ & R₂

• 1800 ohm and 333.3 ohm

• 180 ohm and 333.3 ohm

• 1800 ohm and 3333 ohm

• 1800 k ohm and 333.3 k ohm

In series ohm meter the battery is used continuously .This statement is

• True

• False

An instrument that is used to measure insulation resistance is a-------------