A potentiometer, also referred to as a pot,
is a three-terminal variable resistor that controls voltages, modifies signals,
and tunes electronic circuits. Potentiometer applications include a range of
tasks from audio-level control switching to dimmer switches and sensor
calibration. Potentiometers in these applications provide vital functions in
circuit design.
The knowledge of potentiometer wiring is
fundamental to ensure the proper operation of the intended functionalities of
the potentiometer.
So, let's understand the complete details
of how to wire a potentiometer.
Overview of Potentiometer
Wiring
The potentiometer, also known as
"pot," is a three-terminal variable resistor used to control the
operation of electronic devices by the variation of resistance. It is most
effectively used for operations such as volume control in sound systems,
display brightness control, and tuning of electronic circuits. Potentiometer
wiring becomes critical in such applications for doing proper function.
Potentiometer Symbol
The general symbols show a resistor with an
arrow pointing toward the center to represent the movable wiper terminal. This
is the typical symbol:
Potentiometer Pinout
A typical potentiometer consists of three
pins:
● Pin 1: Fixed terminal A connected to one end of the resistive track
usually connected to VCC (positive voltage).
● Pin 2: Wiper terminal, adjustable middle terminal moving along the
resistive track, is used for varying resistance and output voltage.
● Pin 3: Fixed terminal B connected to the other end of the resistive track,
which is usually connected to GND (ground).
The output voltage will be defined by the
position of the wiper (Pin 2), which acts as a voltage divider between Pin 1
and Pin 3.
Potentiometer Diagram
A basic wiring diagram for the
potentiometer consists of:
● Voltage source connected to Pin 1
● Ground connected to Pin 3
● The output signal is taken from Pin 2
With this setup, the potentiometer
functions as a variable resistor, enabling very fine tuning of Vout.
Different Types of
Potentiometers
Potentiometers come in various types with
certain applications. The key to their differences is their mechanical
configuration and the manner in the resistance is variable. Below are the most
common types of them all.
Linear Potentiometers
Linear potentiometers have a resistive
track with a directly proportional change of resistance to the movement of the
wiper. In other terms, the output voltage is directly proportional to the wiper
position. They are used to implement volume controls, sensors, and
position-sensing systems.
Logarithmic
Potentiometers
Also known as log tapers or log tapers
potentiometers, they have a log-type of response curve. It is a case of small
quantities at the lower positions having a greater effect while the quantities
at the higher positions have minor amounts of change. They are mostly used in
applications of audio controls and man-machine applications where the sense of
the user is closer to a log response.
Rotary Potentiometers
These are the most widely used
potentiometers with the wiper taking a rotary path about a resistive track.
Rotary potentiometers are used within dimmer switches, volume controls, and
industrial automation systems. Both the linear and the log types are provided.
Slide Potentiometers
Also known simply as fader potentiometers,
they have a linear resistive track with the wiper that travels instead of
rotating. Used frequently on mixing consoles of the audio sort, light controls,
and also within applications of motion control.
Trimmer Potentiometers
(Trimpots)
These are small variable potentiometers
that are implemented to carry out calibration and fine-tune applications.
Trimpots are normally mounted on PCB (printed circuit boards) and are driven by
a screwdriver. Trimpots are implemented for circuit calibration, sensor
calibration, and low-maintenance applications.
Digital Potentiometers
Unlike traditional mechanical
potentiometers, digital potentiometers (or digipots) do not have a physical
wiper but work with the aid of electronic controls. Instead of a wiper, they
modify the resistance with the support of built-in ICs (integrated circuits).
They are powered by microcontrollers or digital signals.
Each type of potentiometer is specially
suited to a specific function, and the proper choice is made according to the
requirements of the circuit or device.
Choosing the Appropriate
Potentiometer
Selecting the correct potentiometer is
crucial to supply proper control and durability to the circuit. Different
considerations need to be made to choose a potentiometer to fill a specific
need.
Resistance Matters
The resistance value of a potentiometer
will also measure the current or voltage that can be controlled by it. Common
values include 1kΩ, 10kΩ, 50kΩ, 100kΩ, and others. The right choice depends on
the circuit’s requirements:
● Low resistance (1kΩ –
10kΩ): Suitable for current control applications.
● Medium resistance (10kΩ –
100kΩ): Ideal for voltage control and signal
processing.
● High resistance (100kΩ –
1MΩ): Used in high-impedance circuits such as audio
and sensor applications.
Tolerance
Tolerance indicates the allowable range of
deviation of the potentiometer’s nominal value of resistance. Common tolerances
are between ±5% to ±20%. The lower the tolerance is, the greater the precision
is, which is desirable in calibration networks and measurement instruments.
Power Rating
A power rating indicates how much power a
potentiometer can dissipate without overheating or degradation. Common ratings
range between 0.1W to 2W or higher. For audio control applications where
currents are low, a potentiometer with either 0.25W or 0.5W is fine; other
applications with higher power should call for more sturdy potentiometers.
Type of Potentiometer
The application will specify whether a
rotary, digital, slide, trimmer, log, or linear potentiometer is the best
solution. For example:
● Audio applications → Logarithmic
potentiometer
● Precise calibration → Trimpot
● Automated control systems → Digital
potentiometer
● User-interface controls → Rotary or slide
potentiometer
Physical Dimensions
Potentiometers come in a variety of sizes
and form factors. The specification, therefore, depends on available physical
space on the PCB or for panel-mounted designs. While larger versions can handle
fairly high power, they are not suitable for designs where size is at a
premium.
Mounting Type
Potentiometers can be mounted in different
ways depending on the circuit design:
● Through-Hole Mounting
(THM): Suitable for PCB designs that call for
strong mechanical support.
● Surface-Mount Technology
(SMT): Used on small automated runs.
● Panel-Mounting: Designed to house external user controls such as volume controls and
dimmer switches.
By considering these factors, you can
ensure that the selected potentiometer meets your application’s electrical,
mechanical, and operational requirements.
Potentiometer Wiring
Diagram
Wiring is essential to the functioning of a
potentiometer since the type of potentiometer and its application dictate the
wiring arrangements. Typical wiring arrangements for various types of
potentiometers are shown just below:
Linear Potentiometer Wiring
Diagram
A linear potentiometer is predominantly
used in the application as a voltage divider controlling voltage output.
Therefore, the wiring will be:
● Pin 1: Connect the Power Circuit (VCC or Positive Voltage)
● Pin 2(Wiper Terminal): output variable voltage depending on the position of the wiper.
● Pin 3: earth to ground (GND).
Example Application: Volume control, sensor adjustments.
Logarithmic Potentiometer
Wiring Diagram
A logarithmic potentiometer is widely used
in audio circuits where sound perception follows a logarithmic scale. Wiring is
quite similar to a linear potentiometer:
● Pin 1: Connected to VCC.
● Pin 2: Provides output voltage (variable signal).
● Pin 3: Connected to ground.
Example Application: Audio volume controls, tone adjustments.
Multi-Turn Potentiometer &
Slide Potentiometer Wiring Diagram
● Multi-Turn Potentiometer: Required for high accuracy resistance adjustments. Mainly intended
for calibration circuits. Connection is like a linear potentiometer but very
fine adjustment range in resistance variation can be done.
● Slide Potentiometer: It has kind of same working as rotary potentiometer but its
mechanism is actually based on sliding instead of a rotating knob. It follows
the same wiring principle as linear potentiometers.
Example Applications: Audio mixing consoles for slide potentiometer, fine-tuned sensors for
multi-turn potentiometer.
How to Wire a
Potentiometer?
Wiring a potentiometer correctly ensures it
functions as it is supposed to work whether
it a variable resistor (rheostat) or voltage divider. The procedure of
wiring differs depending on the use of the potentiometer in a circuit.
Stepwise Wiring Guide on Using
Potentiometer:
Identify the Terminals
● Pin 1 (Fixed Terminal A) → Connected to VCC
(positive voltage).
● Pin 2 (Wiper Terminal) → Provides the
adjustable output voltage.
● Pin 3 (Fixed Terminal B) → Connected to GND
(ground).
Determine the Wiring Type
A potentiometer may be connected in two
basic settings:
Voltage Divider Configuration (Most Common Use Case)
This setup provides an adjustable output
voltage:
● Pin 1 → Connect to VCC (+5V, +12V,
etc.).
● Pin 3 → Connect to GND.
● Pin 2 (Wiper) → Provides a variable
voltage output.
Variable Resistor (Rheostat) Configuration
In this mode, the potentiometer acts as a
variable resistor by using only two terminals:
● Pin 1 → Connect to VCC.
● Pin 2 (Wiper) → Connect to the load.
● Pin 3 is left unconnected.
Connect the Potentiometer to
the Circuit
Connect terminals through soldering or
jumper wire to a breadboard, PCB, or control panel. Proper wire insulation to
avoid accidental short circuits.
Test the Potentiometer
● Read resistance or voltage fluctuation with a multimeter while
turning or sliding the potentiometer.
● It must be a smooth transition devoid of all the jumps as output
volts or resistance changes.
With minimal hassle and complete precision,
these steps will put a potentiometer into a circuit.
Advanced Potentiometer
Wiring Usage
Potentiometers are versatile components
that can be used in advanced wiring configurations to attain specific
functionalities. Let us look into advanced wiring configurations and
applications.
Use Shielded Potentiometer
Wiring
Shielded potentiometer wiring is found to
be used in an environment where EMI or RFI affects the quality of the signal.
The shield, basically a conductive material, surrounds the wiring and acts as a
barrier to prevent external noise from interfering with the signal. This kind
of wiring is extensively used in high-fidelity audio and sensitive
measurements.
Use Dual-Gang Potentiometer
Wiring
Dual gang potentiometers are two
potentiometers on a common shaft (or knob) to be controlled simultaneously.
They are installed in stereo audio systems to be used to simultaneously control
both the left and right channels.
In industrial controls, these dual-gang
potentiometers are found wherever multiple circuits must be adjusted
synchronically.
Use Tapered Potentiometer
Wiring
These are taper potentiometers, either
logarithmic or audio taper pots, which exhibit non-linear response
characteristics. They find their main application in audio systems such as
volume control, wherein the human ear perceives variation in sound intensity
logarithmically.
Use Trimmer Potentiometers
Trimmer potentiometers, or trimpots,
consist of a tiny but adjustable potentiometer for fine adjustment or
calibration inside an electronic circuit. Most of them have been mounted
directly onto PCB and adjusted by using a screwdriver. Trimpots find common use
in power supplies, oscillators, and sensor calibration circuits.
Use Potentiometer Splitters
Potentiometer splitters are used for
splitting a single potentiometer's output into several signals. This method is
useful in cases like multi-channel audio mixers or lighting control, where a
single controller must adjust the operation of several different circuits in
unison.
Use Digital Potentiometer
Wiring
Digital potentiometers or digi pots are
electronically controlled devices replicating conventional manual
potentiometers but adjusted with digital signals for use in automated systems,
microcontrollers, and digital circuits where precise, programmable control is
required. Such cases make them suitable for environments wherein manual
adjustment is impractical or impossible to execute.
Conclusion
Potentiometers are electronic component
objects widely used in voltage, resistance, and signal level adjustment in an
admirable variety of electronic circuits. Their proper understanding of wiring
and applications is the key to precision control in audio, sensor, lighting
systems, and industrial automation applications.
Potentiometer types, from basic voltage
divider configurations to complicated digital potentiometer wiring, imply that
proper choice and wiring make for optimum performance. Circuit functionality
and efficiency can be enhanced by applying best wiring practices.
Before selecting a potentiometer you must
consider factors like Resistance value,
power rating, taper type, and mounting style.
