Variable Resistors (Potentiometers, Trimmers)

Variable resistors (potentiometers, trimmers) are electronic components that can change the resistance value and make the electrical current pass less easily. Resistance value can be modified by turning the knob on the variable resistor. They are used in electronic devices for adjusting the volume on radios and amplifiers. 3 types of resistors are available: the inexpensive carbon film types, cermet types with excellent durability and noise characteristics, coiled types that can withstand large currents. Variable resistors differ not only in the variety of resistors, but also in durability, resistance taper and shape. 2 types of resistance taper are available, "A" for logarithmic change against the rotation angle, and "B" for linear change, and they must be selected according to application. Volume type and trimmer type shapes are available, and should be selected according to how frequently the resistance needs to be adjusted.