(1) Synthetic membrane potentiometer. It is represented by the letter WH, as shown in Figure 1. Synthetic membrane potentiometers are usually formed by coating carbon black, graphite, carbon powder, binder, etc. on an insulating body and heating. The resistance range is 100Ω~4.7MΩ, and the power range is 0.1~2W. The synthetic membrane potentiometer features wide resistance range, high resolution, long life, low price, non-linearity, high noise and large temperature coefficient. It is often used in civil low-end products and general instrumentation circuits.
(2) Organic solid potentiometer. It is represented by the letter WS, as shown in Figure 2. Organic solid potentiometers are usually made by hot pressing with carbon black, graphite, carbon powder and organic binders. The resistance range is 100Ω~4.7MΩ, and the power range is 0.25~2W. The organic solid potentiometer is characterized by heat resistance, wear resistance, small volume, strong overload capability, large temperature coefficient, high noise, poor moisture resistance and low precision. It is often used in circuits that require high reliability, temperature, and overload capabilities.
(3) Wirewound potentiometer. It is represented by the letter WX, as shown in Figure 3. The wirewound potentiometer is usually wound on the insulating wire by a wire wound around the insulating substrate and bent into a circular brush. The resistance range is from 14.7 Ω to 100 kΩ, and the power range is from 0.25 to 25 W. The characteristics of the winding potentiometer are high power, high precision, small temperature coefficient, high temperature resistance, good stability, low resolution, and poor wear resistance. High frequency performance and high price, it is often used in high temperature, high power circuits and precision regulation circuits.
(4) Metal glass glaze potentiometer. It is represented by the letter WI, as shown in Figure 4. The metal glass glaze potentiometer is made by mixing and sintering metal powder, glass glaze powder and a binder on a substrate. The resistance range is 100Ω~1MΩ, and the power range is 0.25~0.75W.
(5) cermet fine-tuning resistor, the structure is similar to the metal glass glaze potentiometer, as shown in Figure 5, the resistance range is 20Ω~2M. The power range is 0.5~0.75w.
The cermet trimmer potentiometer is characterized by wide resistance range, small volume, small temperature coefficient, good stability, high resolution and short mechanical life. It is often used to require higher circuit micro-calls.
(6) Digital potentiometer. The common resistance of digital potentiometers is 1kΩ, 2kΩ, 10kΩ, 50kΩ, and 100kΩ. He is characterized by long life, easy digitization, and output as discrete. Commonly used in audio equipment and digital systems, as shown in Figure 6.