EVM-3RSX50B15 Potentiometers, Variable Resistors

Trimmer Potentiometers

The EVM-3RSX50B15 is a trimmer potentiometer that is a three terminal device, consisting of a resistor element with end terminals and a slider. It is usually used in circuits where adjustments need to be made repetitively, and come in a variety of form factors, including through hole and surface mount packages. 

Application Field

Trimmer potentiometers are primarily used for providing input to comparator and other timing circuits. They are often used as a form of tunable inductor in high-frequency signal applications. They are also used for controlling the level of variable DC or AC signals, such as for adjusting the gain of amplifiers and controlling the level of rectifier circuits.

In addition, trimmer potentiometers can be used for controlling digital parameters such as the duty cycle of pulse width modulation (PWM) signals, and adjusting memory timing in microcontrollers.

Working Principle

Trimmer potentiometers are operated using a mechanical arm, usually comprised of a micrometer screw with a pointer attached at its tip. Turning this screw adjusts the resistance between its two end terminals and the wiper or slider terminal. The amount of travel of the wiper is usually limited by a stop.

The resistance of wirewound trimmer potentiometers is higher than rotary rheostats but is lower than potentiometers, typically ranging between 100 Ohms and 10K Ohms. The wattage rating is generally lower than other types of potentiometers, typically ranging between 1/8 W and 1/2 W. The EVM-3RSX50B15 is a 50 Ohm trimmer potentiometer with a 1/4 W wattage rating.

Trimmer potentiometers are usually designed to allow a maximum of about 20 turns of the adjusting screw. The resistance tolerance of the EVM-3RSX50B15 is typically 4%.