3 (a) A resistive displacement transducer with a shaft stroke of 24 mm is applied to the circuit shown.
The applied voltage is 10 V. What is the displacement indicated for 4V voltage reading if the
resistance of output device Rm is infinite. If the resistance of the meter is 10K ohm then what is the %
error in measurement of a displacement of 5mm.
I
A
R.
Wiper
一个
e
Į OR
Rm
R,
e.
I
B
(b) Linearity and sensitivity are two requirements in potentiometer, comment. (7+3)
Answers
Answer:
Resistors provide a fixed value of resistance that blocks or resists the flow of electrical current around a circuit, as well as producing a voltage drop in accordance with Ohm’s law. Resistors can be manufactured to have either a fixed resistive value in Ohms or a variable resistive value adjusted by some external means.
The potentiometer, commonly referred to as a “pot”, is a three-terminal mechanically operated rotary analogue device which can be found and used in a large variety of electrical and electronic circuits. They are passive devices, meaning they do not require a power supply or additional circuitry in order to perform their basic linear or rotary position function.
Variable potentiometers are available in a variety of different mechanical variations allowing for easy adjustment to control a voltage, current, or the biasing and gain control of a circuit to obtain a zero condition.
The name “potentiometer” is a combination of the words Potential Difference and Metering, which came from the early days of electronics development. It was thought then that adjusting large wirewound resistive coils metered or measured out a set amount of potential difference making it a type of voltage-metering device.
potentiometer construction
Today, potentiometers are much smaller and much more accurate than those early large and bulky variable resistances, and as with most electronic components, there are many different types and names ranging from variable resistor, preset, trimmer, rheostat and of course variable potentiometer.
But whatever their name, these devices all function in exactly the same way in that their output resistance value can be changed or varied by the movement of a mechanical contact or wiper given by some external action.
Variable resistors in whatever format, are generally associated with some form of control, whether that is adjusting the volume of a radio, the speed of a vehicle, the frequency of an oscillator or accurately setting the calibration of a circuit, single-turn and multiple-turn potentiometers, trim-pots and rheostats find many uses in everyday electrical items.
The term potentiometer and variable resistor are often used together to describe the same component, but it is important to understand that the connections and operation of the two are different. However, both share the same physical properties in that the two ends of an internal resistive track are brought out to contacts, in addition to a third contact connected to a moveable contact called the “slider” or “wiper”.
Explanation: