Resistive elements are available in two types: carbon and cermet. Their applications in circuits are shown below.
|Application in circuits||Carbon resistive element||Cermet resistive element|
|Voltage division adjustment|
Applications of Trimmer Potentiometers are roughly divided into the following two categories.
With the carbon resistive element type, the secular change of the resistance as a result of exposure to high temperature or humidity is rather great. However, since the resistance changes uniformly throughout the entire resistor, the ratio of the resistance (resistance setting stability, or RSS; see Terms) barely changes.
Therefore, this type is generally used for voltage division adjustment. However, when the total resistance change (fluctuation TR) is within the circuit tolerance, this type can be used for current adjustment.
With the cermet resistive element type, the secular change of the resistance as a result of exposure to high temperature or humidity is small. Therefore, this type is used both for voltage division adjustment and current adjustment.
Below are the results of environmental tests (fluctuation TR and RSS) on PVZ3 Series carbon resistive element Trimmer Potentiometers and PVA2 Series cermet resistive element Trimmer Potentiometers.