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Resistors

Technical Guide of Trimmer Potentiometers

Series

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 round round
Current adjustment triangle round

Applications of Trimmer Potentiometers are roughly divided into the following two categories.

  • Voltage division adjustment: A certain voltage is obtained from the ratio of the resistance.
  • Current adjustment: A current value is determined from the magnitude of resistance.

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.

Test graph

Test item: High temperature exposure
Test condition: 70°C, 1000h

PVZ3A103C01B00 (Carbon resistive element)
PVA2A103C01B00 (Cermet resistive element)
PVZ3A103C01B00 (Carbon resistive element)

PVZ3A103C01B00
(Carbon resistive element)

PVA2A103C01B00 (Cermet resistive element)

PVA2A103C01B00
(Cermet resistive element)

Test item: Humidity exposure
Test condition: 70°C, 95%RH, 1000h

PVZ3A103C01B00 (Carbon resistive element)
PVA2A103C01B00 (Cermet resistive element)
PVZ3A103C01B00 (Carbon resistive element)

PVZ3A103C01B00
(Carbon resistive element)

PVA2A103C01B00 (Cermet resistive element)

PVA2A103C01B00
(Cermet resistive element)

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