TrimPot | Preset |Types


Trim-pot is also known as Trimmer Potentiometer. Trim-pots are very small in size and one of the variable resistors. It is a three-terminal device, and it has a knob to vary the resistance manually. Due to their size, these are widely used in PCB mounting. Trim-Pots are designed for highly sensitive tuning devices, so by using this device we can get highly calibrated readings. 

Other names: Preset, Variable resistor.

Other related devices: Potentiometer, SMD Potentiometer, Digital potentiometer

What is Trim-Pot

In general, it is called a potentiometer, variable resister, preset, and Trimmer Potentiometer but there are slight variations in all like (size, power handling, calibrated readings).

3006P-103 Trim-pot

NOTE: If the Trim-Pot can be used as a variable resistor then it called Preset, Trim-Pot is used for tuning and calibration in designs.

Trim-pot Consists of:

1. Resistive Element

2. Wiper unit (Movable contact) 

3. End terminal

4.Contact Actuator  (Adjustable Skrew, Knob)

Difference between preset and potentiometer

Preset and potentiometer are worked like same and the resistance values are the same

  • For example the same 10kΩ resistance value is available in preset and potentiometer, but the difference is how much amount of power it can handle.
  •  Preset are used to handle the less amount of power, the potentiometer is used to work with high power ratings.
  • Preset designed for PCB mount, the potentiometer is designed with variable knob (example volume controller)
  • Preset are available in small packages, the size of potentiometer is bigger than the preset.


What is the need of Preset-Trimpot

 Fixed Resistors

The value of the resistor is fixed, does not change by the user for example consider 100kΩ resistor its value  is fixed we can not change its value

Problem with fixed resistors

We are going to design a system based on the properties of the components, unfortunately, there is a chance to change the some property of the component, then the design will failure

In this type of situation if we use the preset we can change the resistance at any time

Preset or Trimpot Advantage

Preset or Trimpot are used for PCB circuit designs, they are available in small packages, in any circuit designs  to set the variable resistance we need to use the preset or Trimpot, these allow the user to change the resistance even after the circuit design is completed due to this we can set the sensitivity of the circuit at any time by varying the resistance.

Types of Trim-pot

1. Multi-Turn-Trim-pot

Multi-Turn gives high precise value than Single-Turn, so it performs multiple rotations (turns) from 0-25 turns, these are highly used in Tunning Circuits, these can be manufactured with Wire-Wound or Cermet materials.

    Cermet Trim-pot Resistance range: 10 ohms to 10M ohm

    wire wound Trim-pot Resistance range: 10 ohm to 50K ohm

Lead-Screw Actuated (Multi-turn-trimmer)

    Turns: 15-25
    Shap: Rectangular Case
    Wiper Unit: Linear wiper path
    Standard Resistors in Wire-Wound: 3005 3010, 3057.
    Standard Resistors in Cermet: 3012, 3059, 3082, 3006.

  Warm-Gear Actuated (Multi-turn)

      Turns: 10-25
      Shape: Square Case
      Wiper Unit: Circular wiper movement
      Standard Resistors in Wire-Wound: 3250, 3260, 3290.
      Standard Resistors in Cermet: 3252, 3292, 3299.

1. Single-Turn:

Single-Turn adjustment not as precise as Multi-Turn-presetit turns only one rotation(360-Degrees), due to its functionality it gives only a few readings.




Example: Min-0v,  Max -5v
                readings : 0v, 1v, 1.5v,2v,3v,3.5v.4v,4.5,5v.

Standard Resistors in Wire-Wound: 3305.3345.
Standard Resistors in Cermet: 3329,3339,3352, 3386.

 Surface Mount - SMD (Single-Turn-preset)

        Surface Mount Trimmer leads solder to surface of the board to save space and improve performance
Shape: Rectangular, Round cases
Wiper Unit: Circular

 Center-Tap (Single-Turn-preset)

Center-Tap divides the Potentiometer into two separate independent units. Especially useful in op-amp applications



  • OP-AMP Zero adjustment (Multi-Turn-preset)
  • Oscillators frequency adjustment (Multi-Turn-preset)
  • Voltage Regulators (Single -Turn-preset)
  • Volume controllers
  •  Multi vibrators
  • Adjust the sensitivity of a design.

IEC Standard

Trim-Pot Resistor


Other Articles

Digital Potentiometer






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