This question was previously asked in. Square law Non linear Logarithmic Uniform. Dynamometer type instruments: Dynamometer type instruments working on the principle of " Changing the mutual inductance. There are two types of coils in this instrument. The fixed coil also called the Current coil and the moving coil named the Pressure coil.
Dynamometer develops deflected torque T d by the interaction of magnetic fields. Dynamometer instrument can be used as Ammeter, Voltmeter, and Wattmeter. But it is more effective in the Wattmeter type because power is proportional to the square of the current. The scale is uniform in the Wattmeter type. While using it as Ammeter its scale is square-law scale non-uniform because of the deflecting torque. Thus, the instantaneous value of the deflecting torque is proportional to the instantaneous power.
Owing to the inertia of the moving system, the pointer reads the average power. In dc circuits, the power is given by the product of voltage and current, and hence the torque is directly proportional to the power. Thus, the instrument indicates the power. Get Started for Free Download App. Which of the following principles is utilised in an electrodynamometer type instrument? Which type of scale does a dynamo type wattmeter possess?
In a low power factor wattmeter compensating coil is connected:. Which of the following meters is the most accurate instrument for measuring AC signals with frequencies lower than Hz? Which of the following statements is not an advantage of Electrodynamic instruments? You are to examine these two statements carefully and select the answer using the codes given below: Statement I : In an ac dynamometer-type wattmeter the instantaneous value of developed deflecting torque is proportional to the product of voltage and current in the respective coils at the corresponding instant, the constant of proportionality is the same as in the case of dc use.
Statement II : The moving system of the meter is prevented by its Inertia from following the variations in the deflecting torque which takes place during each cycle, and takes up a position corresponding to the average value of the torque. Following statements are given for electrodynamometer-type instruments: a It is used for a. Electro dynamometer type of instruments are enclosed in a casing made up of high permeability material to:.
The scale of an electrodynamometer usually reads the:. What sensor provides a dc voltage approximately 1 V at 10 mW? Diode sensor B. Thermocouple sensor C. Thermal sensor D. Thermistor sensor Fluid friction damping is employed in one of the following A.
Dynamometer wattmeter B. Induction type energy meter C. Hot-wire ammeter D. Kelvin electrostatic voltmeter Low resistance resistor B. High resistance resistor C.
High voltage transistor D. Capacitor Permanent- magnet moving coil instrument can be used in A. Cathode B. Control grid C. Anode D. Phosphor screen Logarithmic nulling B. Orthogonal nulling C. Exponential nulling D. Linear nulling Because of effective eddy current damping B. Because external magnetic field has no effect C. Because it is spring controlled D. Because it has no hysteresis loss Thermal converters B.
Thermal sensors C. Thermocouple sensors D. Diode sensors Voltmeter B. Signal generator C. Grid-dip meter D. Absorption meter Shunts are generally made of what material? Constantan B. Manganin What meter is the most sensitive? Which movement is the most expensive?
D Arsonal movement B. Moving-iron D. Iron-wave Attraction and repulsion instruments are considered as A. Moving-cell instruments B. Moving-iron instruments C. Electrodynamic instruments D. Dynamometer In Wheatstone bridge, bridge balance is considered where A. There is no current that flows through the load B. There is current that flows through the load C. There is potential difference between load terminal D. The galvanometer reading is maximum The temperature coefficient of resistance of the shunt material is A.
Deflecting force D. Force at rest A small swamping resistance is connected in series with operating coil of a moving coil ammeter in order to compensate for the effects of A. Temperature variation B. Hysteresis C. External magnetic fields D. Temperature inversion The typical power range of diode sensor is A. Spectrum analyzer B. Oscilloscope C. Field strength meter D. Milliammeter What dc bridge is widely used for the accurate measurements of resistance?
Owen bridge B. Hay bridge C. Potentiometer bridge D. Wheatstone bridge Wheatstone bridge B. Potentiometer bridge C. Kelvin bridge D. Owen bridge Majority of analog measuring instrument utilizes one of the following effects.
Heating effect B. Electrostatic effect C. Magnetic field D. Chemical effect Dynamometer type instrument can be used for A. Permanent-magnet C. Hot-wire D. Iron-wire The frequency of rotation in some rotating machinery can be measured by a A. VTVM B. Tachometer C. Spectral meter D. Stroboscope Which of the items below describes an absorption meters usage?
Check the output frequency of a transmitter B. Monitors the output current of a receiver C. Monitors the frequency ratio of a device D. Frequency generator What instrument is used for observing voltage and current waveforms? Multimeter B. DMM C. Oscilloscope D. Telescope Which of the following forces does not act on the moving systems of analog instruments?
A deflecting force B. A controlling force C. A damping force D. An electrostatic force When current through the operating coil of a moving-iron instrument is tripled the operating force becomes A. What is the typical full-scale deflection current of a moving coil instrument? What instrument is used for measuring the amount of current flowing in a circuit?
Ammeter C. Meter amperage VOM B. VTVM C. DMM D. DTMF What is the typical full-scale voltage across a moving coil voltmeter? What is the period of a repetitive signal? One-fourth cycle of the waveform B. Two cycles of the waveform C. One cycle of the waveform D. One-half cycle of the waveform What element of a CRT releases electrons when heated indirectly by a filament? Grid C. Moving-iron instrument has what scale? Uniform B. Logarithmic C. Squared D. Exponential A pattern displayed by oscilloscopes which has a steady characteristic is called A.
Lissajous pattern B. Nyquist pattern C. Barkhausens criterian D. Fermats pattern Which of the following extends the range of a moving-iron ac ammeter? A shunt B. A multiplier C. Changing number of turns of operating coil D. A series Which part of the following is not a basic part of a CRT? Electron gun B. Focusing and accelerating elements C. Horizontal and vertical deflecting plates D. Sawtooth generator Horizontal B. Diagonal C.
Vertical D. Voltage What ammeter is used to measure high-frequency currents? Hot-wire B. Moving-iron C. Dynamometer D. Thermocouple Which of the voltmeter is used for measuring high direct voltage say 10kV? Permanent-magnet moving coil B. Hot-wire C. Moving iron A common technique for measuring power at high frequency is to A.
Television B. Computer C. Meter face D. CRT Electrostatic instruments are exclusively used as A. What is the typical power range of thermocouple sensors A. An electric pyrometer is an instrument used to measure A. Which instrument is the most sensitive? Which is the most commonly used induction type instrument?
Induction voltmeter B. Induction watt-hour meter C. Induction wattmeter D. Induction ammeter What type of instrument is the watt-hour meter?
An integrating B. An indicating D. A power meter A certain pulse measures 10ms and has a period of 50ms. The duty cycle is A. At beginning B. At half of full C. At ending D. Any part One of the basic functions of electronic circuit is A. Cathode ray oscilloscope CRO B. Cathode ray tube CRT C. Spectrum analyzer D. VTVMs Considered as the heart of the cathode ray oscilloscope.
Cathode ray tube CRT B. Sawtooth generator C. Horizontal amplifier D. Vertical amplifier A material that glows when struck by the energetic electrons in a CRT. Aquadag B. Silicon C. Germanium D. Phosphor
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