DEE10133 CHAPTER 1 : DC METER

Figure shows an internal resistance 100Ω and 5mA as a total current used in series ohmmeter with R1 = 300Ω, R2 = 200Ω and V = 9V. Hence, calculate the value of Rx.

(a)  

Name this circuit

(a)  

In moving coil instrument consists of 110 turns wound on a square former length 1cm and 1.5cm wide. The flux density in the air gap is 0.07T. Determine the deflecting torque on the coil when carrying a current of 13mA

• 30µNm

• 15µNm

• 20µNm

• 45µNm

Why the pointer oscillate?

• Pointer torque

• Controlling torque

• Damping torque

• Deflecting torque

Calculate the sensitivity of a 200mA meter movement which is to be used as a DC voltmeter.

(a)  

Refer to the table, which meter that have less loading effect?

(a)  

A PMMC instrument with a full scale deflection of 40μA and an internal resistance of 500Ω is used as a voltmeter. Determine the value of the multiplier resistance needed to measure a voltage range of 0-10V.

(a)  

Choose the correct description for DC Voltmeter

• A small value multiplier resistor is connected in parallel to a PMMC meter movement

• A large value multiplier resistor is connected in parallel to a PMMC meter movement

• A small value multiplier resistor is connected in series to a PMMC meter movement

• A large value multiplier resistor is connected in series to a PMMC meter movement

To build a circuit for a double range DC ammeter, ______________ shunt resistors m,ust be connected in ____________ with the meter movement.

• two, series

• three, series

• two, parallel

• three, parallel

A PMMC instrument can be used as _________ by connecting it with a low resistance shunt.

• Voltmeter

• Galvanometer

• Ammeter

• Wattmeter