Potentiometer manufacturers teach you potentiometer selection ideas2021

Potentiometer is a kind of electronic components commonly used in circuits. Friends who purchase potentiometers often only look at the surface and do not really understand the potentiometer when choosing a potentiometer. When selecting a potentiometer, you should first consider the following aspects Consider: the type of potentiometer, the selection of resistance change characteristics, the parameters of the potentiometer, and the structural requirements.

1. Choose the type of potentiometer according to the requirements of use

Generally speaking, in circuits with low requirements, or where the environment is better, synthetic carbon film potentiometers should be selected first. Synthetic carbon film potentiometer has the characteristics of high resolution, wide resistance range, complete varieties and models, and low price. However, it has the shortcomings of poor moisture resistance and poor stability. It can be widely used in household appliances that work indoors. For example, the volume potentiometer with switch used in semiconductor radios can be a synthetic carbon film potentiometer; the power adjustment circuit in a TV can be a direct sliding carbon film potentiometer; the high load and fine-tuning potentiometers in other household appliances can also Optional synthetic carbon film potentiometer. In addition, the synthetic carbon film potentiometer has a long mechanical life and can be used in circuits that require long wear life.

If the circuit needs to be adjusted precisely and consumes a lot of power, wirewound potentiometers should be used. Wirewound potentiometers are only suitable for low-frequency circuits due to their large distribution parameters, so wirewound potentiometers should not be used in high-frequency circuits. In addition, the noise of the wirewound potentiometer is small, and this type of potentiometer can be used for circuits that require low noise.

The metal glass glaze potentiometer has a wide resistance range, high reliability, good high frequency characteristics, good temperature resistance, and good humidity resistance. It is the preferred type of potentiometer for circuits and precision electronic equipment with higher operating frequencies. In addition, the metal glass glaze trimming potentiometer can be used in small electronic devices.

2. The resistance change characteristics should be selected according to the purpose

The resistance change characteristics of the potentiometer should be selected according to the purpose. For example, the volume control potentiometer should be the exponential potentiometer first. If there is no exponential potentiometer, it can be replaced by a linear potentiometer, but logarithmic potentiometers cannot be used, otherwise the volume adjustment range will be reduced; The potentiometer used for pressing should be a linear potentiometer; the potentiometer used for tone control should be a logarithmic potentiometer.

3. Select the parameters of the potentiometer according to the requirements of the circuit

The parameters of the potentiometer mainly include the nominal resistance, rated power, maximum working voltage, linear accuracy and mechanical life, etc., which are the basis for selecting the potentiometer. When the type of potentiometer is selected according to the use requirements, the technical and performance parameters of the potentiometer must be selected according to the requirements of the circuit.

The mechanical life of different potentiometers is different. Generally, the mechanical life of synthetic carbon film potentiometers is the longest, up to 200,000 weeks, while the mechanical life of glass glaze potentiometers is only 100-200 weeks. When choosing a potentiometer, you should choose potentiometers with different mechanical life parameters according to the different requirements of the circuit for wear resistance.

4. Pay attention to the structural requirements

When choosing a potentiometer, pay attention to the size of the potentiometer, the length of the shaft and the style of the shaft end, and whether the position on the shaft needs to be locked, single or multi-connected, single-turn or multi-turn, etc., for the specific structure Claim.

For potentiometers that need to be adjusted frequently, you should choose a potentiometer whose shaft end is milled into a plane to install the knob. For potentiometers that do not need to be adjusted frequently, you can choose a potentiometer with a groove on the shaft end so that it will not rotate after adjustment with a screwdriver to maintain the relative stability of the working state. For potentiometers that require accuracy and will not change once they are adjusted, a potentiometer with a locking device should be selected.

Potentiometer with switch, the switch part is used for on-off control of the circuit power supply, and the potentiometer part is used for the adjustment of the electric quantity. There are single-pole single-throw, single-pole double-throw, double-pole double-throw, etc. for the switch with switch potentiometer. The selection should be determined according to the needs. Potentiometers with switches are divided into push-pull switch potentiometers and rotary switch potentiometers. When the push-pull switch potentiometer is switched on and off, its moving contacts do not participate in the action. The advantages of this are: firstly, there is no wear on the resistor body, and secondly, it will not change the position of the installed potentiometer. Each time the switch of the rotary potentiometer is actuated, the movable contact will slide on the resistor body once, so the wear is large, which will affect the service life of the potentiometer.

The single potentiometer is used to adjust the single power. The potentiometer used to adjust the volume and tone of the two channels in the radio cassette recorder, CD player and other stereo audio equipment should choose the double potentiometer.