What is a Trimmer Resistor Working & Its Applications

A trimmer resistor is a resistor that can be set or “trimmed” to a precise resistance value by turning a screw. This type of resistor is commonly used in circuits as it allows the performance of the circuit to be adjusted. The adjustment is done by using a tool, like a screwdriver to rotate the dial or knob of the device.

Working on Trimmer Resistor

The working principle of a trimmer resistor is very simple. A resistive element is a thin film deposited on an insulator. The current will flow when the thin film contact end is pressed against the external pin, but no current will flow if it is not pressed.

Symbol of Trimmer Resistor

Types of Trimmer Resistors

  • Single-turn Trimmer Resistors
  • Multi-turn Trimmer Resistors
  • Surface Mount Trimmers

Single-turn Trimmer Resistors

  • They have screws that can be rotated about 300 degrees in either direction to adjust the resistance.
  • The range of resistance value of this type is about 10Ω to 1MΩ, adjustable in increments of up to 0.01Ω.
  • This type of trimmer resistor can handle up to 1W of power.

Multi-turn Trimmer Resistors

  • They work like single-turn trimmers, except they have multiple turns (usually 5) to provide a wider range of adjustment about 50Ω-1MΩ.
  • This type of trimmer resistor can also be adjusted in increments of up to 0.01Ω.
  • This type of trimmer resistor can only handle 0.25W of power, making it less powerful than a single-turn trimmer.

Surface Mount Trimmers

  • This type of trimmer resistor is specifically designed to be surface mounted on a printed circuit board.
  • They are used in applications where voltage or current needs to be regulated, and their small size makes them suitable for small electrical devices such as mobile phones.

Applications of Trimmer Resistor

  • Stereo system and audio
  • Radio-frequency (RF)
  • Dialysis machines
  • Adjustable voltage dividers

Leave a Comment