Electronic Comparators
Electronic Comparator
In electronic comparator, transducer induction or the
principle of application of frequency modulation or radio oscillation is followed.
Construction details:
In the electronic comparator, the following components
are set as follows:
i. Transducer
ii. Oscillator
iii. Amplifier
iv. Demodulator
v. Meter
(i) Transducer: It converts the
movement of the plunger into an electrical signal. It is connected with
oscillator.
(ii) Oscillator: The oscillator
which receives electrical signal from the transducer and raises the amplitude
of frequency wave by adding carrier frequency called as modulation.
(iii) Amplifier: An amplifier is
connected in between oscillator and demodulator. The signal coming out of the
oscillator is amplified into a required level.
(iv) Demodulator: Demodulator is
a device which cuts off external carrier wave frequency. i.e. It converts the
modulated wave into original wave as electrical signal.
(v) Meter: This is a
display device from which the output can be obtained as a linear measurement.
Working principle:
The work to be measure displaced
under the plunger of the electronic comparator. Both work and comparator are made
to rest on the surface plate. The linear movement of the plunger is converted
into electrical signal by a suitable transducer. Then it sent to an oscillator to
modulate the electrical signal by adding carrier frequency of wave. After that the
amplified signal is sent to demodulator in which the carrier waves are cut off.
Finally, the demodulated signal is passed to the meter to convert the probe tip
movement into linear measurement as an output signal. A separate electrical
supply of D.C. is already given to actuate the meter.
Advantages of Electrical and
Electronic comparator:
1) It has less number of moving parts.
2) Magnification obtained is very high.
3) Two or more magnifications are provided in the same
instrument to use various ranges.
4) The pointer is made very light so that it is more
sensitive to vibration.
5) The instrument is very compact.
Disadvantages of Electrical
and Electronic comparator:
1) External agency is required to meter for actuation.
2) Variation of voltage or frequency may affect the
accuracy of output.
3) Due to heating coils, the accuracy decreases.
4) It is more expensive than mechanical comparator.