All Electronics has a large selection of trimmer potentiometer available, including single and multi-turn trimpots in a wide range of ratings and mounting styles. A trimpot or trimmer potentiometer is a small potentiometer which is used for adjustment, tuning and calibration in circuits. When they are used as a variable resistance (wired as a rheostat) they are called preset resistors. Trimpots or presets are normally mounted on printed circuit boards and adjusted by using a screwdriver. Single turn trimmers/presets are very common and used where a resolution of one turn is sufficient. For higher adjustment resolutions, multi-turn trimpots are used.