Question

The optical Tachometer

a- Can the SIS optical tachometer be used to determine the direction of rotation?
b- If number of slots in the disc is changed what effect would this have on the results?
c- Discuss sensor characteristics as linearity, repeatability, accuracy and sensitivity.
d- What are the sources of errors in this experiment?

Answer 1

a) The optical tachometer is a device that is used to measure the speed of the disc or the shaft . The speed of roation is measured in terms of revolutions per minute . But the optical tachometer does not give sense (direction) of motion .

b) If the number of slots are changed on disc the resolution of the result changes . i.e. if number of slots are decreased we get an approximate answer . The accuracy of the result increases with the increasing number of slots on the disc .

c) Sensor characteristics:-

Linearity- It is the characteristic by virtue of which the variation in observations is linear i.e. straight line

Accuracy - Accuracy is the difference between the observed value and actual value . It tells us how accurate is the value observed

Sensitivity- It is the ratio of magnitude of output signal to the magnitude of input signal. It actually defines how large the response of the sensor is to a small change in input.

d) The various sources of error in tachometer experiment are :-

Personal error(not taking the actual reading ) , systematic error ( not putting tachometer in contact correctly ) , instrumental errors (non calibrated tachometer ) , errors due to natural causes .

Thank You!!