Electrical Measurements & Measuring Instruments Multiple Choice Questions on “Introduction of Bridges”.
1. A bridge circuit is used for the measurement of which of the following components?
a) Resistance, capacitance, and inductance
b) Diode, triode, and thyristor
c) Transistor, thermistor, and antenna
d) LED, op amp, and transducer
Clarification: A bridge circuit is basically used for the measurement of basic electronic components such as resistance, capacitance, and inductance.
2. A simple bridge circuit consists of a network of __________
a) 3 resistance arms
b) 2 resistance arms
c) 4 resistance arms
d) 6 resistance arms
Clarification: A simple bridge circuit is made of a network consisting of 4 resistance arms. Usually a galvanometer is connected between the ends of the opposite two junctions in order to measure the flow of current.
3. What is applied to the two opposite junctions of a bridge circuit?
a) source of voltage
b) source of current
c) source of power
d) source of impedance
Clarification: A current source is connected between the two opposite junctions of a bridge circuit. Deflection of the galvanometer in the circuit indicates the flow of current.
4. A bridge circuit uses which method of measurement?
Clarification: A bridge circuit makes use of a comparison measurement method. In this method the bridge compares the value of an unknown component with a standard value of a given component.
5. Which principle operates a bridge circuit?
a) null indication
b) ampere’s rule
c) partial indication
d) kirchhoff’s laws
Clarification: A bridge circuit operates on the principle of null indication. Based on the deflection of the galvanometer, current flows between the two opposite junctions.
6. The accuracy of a bridge depends on the _________
a) null indicator
b) bridge components
c) current source
d) voltage source
Clarification: As a bridge circuit compares the value of an unknown component with the value of a standard, it’s accuracy depends on the bridge components.
7. When is the bridge circuit balanced?
a) When voltage is applied
b) When current flows through the opposite ends of the bridge circuit
c) When no current flows through the galvanometer
d) When impedance is minimum
Clarification: The bridge circuit is said to be balanced when no current flows through the null indicator which is generally a galvanometer.
8. Relationship at balance condition between the component values of the four arms of a bridge is known as _________
a) full load condition
b) open circuit condition
c) short circuit condition
d) balancing condition
Clarification: During balance condition or equilibrium there exists a certain relationship between the component values of the four arms of the bridge. This relationship is known as the balancing condition or balancing equation.
9. D.C. bridges are used for _________
a) measurement of resistance
b) measurement of capacitance
c) measurement of current
d) measurement of inductance
Clarification: Resistance measurements are done by making use of a suitable D.C. bridge.
10. What is used to characterize single port devices, multiport devices, etc?
a) current values
b) impedance values
c) voltage values
d) power values
Clarification: Impedance values are used to characterize one port devices, networks, multiport devices and other systems.