Which instrument measures electrical current directly?
A Voltmeter
B Ammeter
C Wattmeter
D Galvanometer
Ammeters are designed to measure the flow of electric current in amperes by being connected in series with the circuit.
What type of transformer is used to measure high currents in power systems?
A Auto transformer
B Current transformer
C Distribution transformer
D Potential transformer
Current transformers step down high currents to lower levels suitable for measurement and protection in electrical circuits.
Which device is used to measure phase difference between two AC signals?
A Oscilloscope
B Phase meter
C Wattmeter
D Multimeter
Phase meters are used to measure the phase difference between two AC signals, expressed in degrees.
What does a tachometer measure?
A Voltage
B Speed of rotation
C Resistance
D Inductance
Tachometers are instruments that measure the rotational speed of an object, commonly in revolutions per minute (RPM).
What is the principle of operation of a piezoelectric transducer?
A Resistance change with temperature
B Electrical voltage generated under mechanical stress
C Magnetic induction
D Capacitance variation
Piezoelectric transducers generate electrical signals when subjected to mechanical stress, utilizing the piezoelectric effect.
What is the purpose of a galvanometer?
A Measure current
B Measure small currents
C Measure voltage
D Measure power
Galvanometers are sensitive instruments used to measure small electrical currents, typically in microamperes.
Which bridge is used to measure inductance?
A Schering bridge
B Maxwell bridge
C Kelvin bridge
D Wheatstone bridge
Maxwell bridges are designed for precise measurement of inductance in AC circuits.
What does a frequency meter measure?
A Voltage
B Frequency of AC signals
C Current
D Energy consumption
Frequency meters measure the frequency (number of cycles per second) of an AC signal, expressed in Hertz (Hz).
Which transducer is used for temperature measurement?
A Strain gauge
B Thermocouple
C LVDT
D Pressure sensor
Thermocouples measure temperature by generating a voltage based on the temperature difference between two junctions.
What is the principle of a current transformer (CT)?
A Electromagnetic induction
B Electromagnetic induction to step down current
C Capacitive effect
D Piezoelectric effect
Current transformers use electromagnetic induction to step down high current to lower levels suitable for measuring and protection.
Which material is most commonly used in a galvanometer coil?
A Copper
B Aluminum
C Iron
D Steel
Galvanometers typically use coils made from aluminum due to its low weight and high conductivity.
What does an oscillograph measure?
A Frequency
B Time-dependent electrical signals
C Power consumption
D Current levels
Oscillographs are used to measure time-dependent electrical signals, typically represented as waveforms.
What does a pressure transducer measure?
A Flow rate
B Pressure
C Displacement
D Speed
Pressure transducers measure the applied pressure, often converting it into an electrical signal for further processing.
Which device is used to measure the temperature of an object?
A Thermometer
B Thermocouple
C Strain gauge
D Pressure gauge
Thermocouples measure temperature by generating a voltage based on the temperature difference between two different materials.
What is the purpose of a signal conditioner?
A To measure displacement
B To amplify and filter raw signals
C To store signals
D To transmit signals wirelessly
Signal conditioners prepare raw signals from sensors or transducers by amplifying, filtering, and converting them into usable formats.
What is the primary purpose of a dynamometer-type wattmeter?
A To measure average power in AC and DC circuits
B To measure instantaneous voltage
C To measure current
D To measure resistance
Dynamometer-type wattmeters measure average power in both AC and DC circuits by utilizing the interaction of magnetic fields.
What is the function of a potentiometer in electrical measurements?
A To compare unknown voltage with a reference
B To measure current
C To measure temperature
D To measure resistance
A potentiometer is used to compare an unknown voltage with a reference voltage for precise measurement of voltage.
What is the primary use of a Kelvin bridge?
A To measure low resistance accurately
B To measure capacitance
C To measure voltage
D To measure frequency
Kelvin bridges are designed to measure low resistances accurately by eliminating the effects of contact resistance and lead resistance.
What is the primary purpose of a current transformer (CT)?
A To step down current for measurement
B To step up voltage
C To step down voltage for measurement
D To measure resistance
Current transformers (CTs) step down high currents to lower, measurable levels, making them ideal for metering and protection.
Which instrument is used to measure small voltages accurately?
A Galvanometer
B Voltmeter
C Ammeter
D Wattmeter
Galvanometers are designed to detect and measure very small voltages or currents by utilizing the deflection of a needle within a magnetic field.