Difference between Analog Potentiometer,Digital Potentiometer
This page compares Analog Potentiometer (Pot) vs Digital Potentiometer (Pot) and mentions difference between Analog Potentiometer and Digital Potentiometer. Analog pot is also known as mechanical potentiometer and digital pot is known as electronic potentiometer due to their construction. It also mentions benefits or advantages of these potentiometer types.
It 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.
Analog Potentiometer | Mechanical Potentiometer
• The figure-1 depicts analog or mechanical potentiometer.
It consists of resistive element with sliding contact which can be rotated
manually using hand.
• As shown, there are three terminals. Between the two of the terminals there is resistive element. The third one viz. wiper is connected across various points along the resistive element.
• In this pot type, wiper is physically moved by hand. The three terminals are +5V, Measure and GND. The two terminals "Measure" and "GND" provide variable voltage when wiper is moved or rotated.
• Due to its construction and function, analog potentiometers are called as mechanical potentiometers.
➨Advantages: It is simple, inexpensive and compact. It is used as digital gain control.
Digital Potentiometer | Electronic Potentiometer
• The figure-2 depicts digital or electronic potentiometer. It consists of interface, control and registers.
Input signals to digital section are external control signals from serial bus.
Outputs (from digital section) are internal signals stored in internal
volatile and nonvolatile registers or signals which move the wiper.
Nonvolatile digital pots can retain resistance value regardless of external
• In this pot type, wiper is digitally controlled either by computer or microcontroller or microprocessor. The resistance between two terminals can be adjusted using these digital input signals similar to analog potentiometer.
• Serial buses can be either asynchronous or synchronous. The most common asynchronous interface bus is increment/decrement interface (U/D', INC', CS') . The most common synchronous interface bus is I2C, SPI, Two-wire, microwire etc.
• The common signals are clock, data-in, data-out, control and address.
• Due to its construction and function, digital potentiometers are called as electronic potentiometers.
• Examples of digital potentiometers: MAX5427/MAX5428/MAX5429 linear digital potentiometers from Maxim Integrated, AD5171 (I2C controllable ) and AD5206 (SPI controllable) from Analog devices Inc.
➨Advantages of digital potentiometer compare to analog potentiometer are as follows:
• More reliable compare to mechanical potentiometers,
• Space savings
• Wide range of resolution
• Insensitive to harsh environment
• Available in volatile and non-volatile types
• Much more writing cycles than mechanical parts