Difference between Linear Potentiometer,Rotary Potentiometer
This page compares Linear Potentiometer vs Rotary Potentiometer and mentions difference between Linear Potentiometer and Rotary Potentiometer.
Potentiometer is a three terminal device with rotating or sliding contact which forms adjustable voltage divider. It functions as variable resistor or rheostat when two terminals are used (one end and wiper). Potentiometer has wide variety of applications such as volume or tone controls in audio systems, as position sensor (or transducer) in joystick etc.
• The figure-1 depicts linear potentiometer.
It contains electrical resistance in the form of straight section of track.
The track may consist of strip of resistive polymer or insulator with coil of nichrome wire
wrapped around it.
• For sensing application, potentiometer is wired as voltage divider. For the same, fixed potential is applied across its full length as shown in the figure-1.
• As shown wiper slides along the track, hence sensing voltage varies linearly with position of the wiper. Hence it is known as linear potentiometer.
• It can be used directly to control analog indicator in a analog meter. It can also be processed by ADC (Analog to Digital Converter) for further processing.
• Example: Linear potentiometers from companies such as Bourns.
• Advantages: Simple, inexpensive, compact, requires few components.
• Disadvantages: Though the track contains lubricant, some wear occurs as a result of motion of the wiper contact. Life expectancy is reduced by vibration or by contamination due to dirt/moisture.
• Refer difference between analog potentiometer and digital potentiometer >>.
• Rotary potentiometer is categorized into arc-segment rotary potentiometer and multiturn rotary
• The figure-2 depicts rotary potentiometer of arc segment type. This type is most common compare to multiturn type.
• As shown, it contains resistor in the shape of an arc, referred as track. It may be strip of resistive polymer or may consist of insulator with coil of nichrome wire wrapped around it.
• Wiper slides along the track, sensing a voltage that varies linearly with angular position of the wiper.
• The advantages and disadvantages of rotary potentiometer is same as mentioned for linear potentiometer.
Rotary encoder basics and types
• Rotary encoder is type of position sensor used to determine angular position of rotating shaft.
• It generates electrical signal which is either analog or digital.
• The electrical output is sensed or used by micro-controller board or arduino to perform desired action.
• Refer Rotary encoder basics and types >>.