POLYSHINEHK / TECHNICAL GUIDE
Rotary potentiometers: a practical technical guide
A rotary potentiometer is a three-terminal variable resistor adjusted by turning a shaft. This guide explains how the parts of a rotary potentiometer work together, which parameters matter when specifying one, and the exact values we manufacture on our 9 mm F09K series.
How a rotary potentiometer works
Two outer terminals connect the ends of a resistive track; the centre terminal connects to a wiper that slides along that track as the shaft rotates. Wired across the full track it works as a voltage divider; wired to one end and the wiper it works as a simple variable resistor.
The resistive track can be carbon film (cost-effective, the usual choice for audio and general control) or conductive plastic. The relationship between shaft angle and output is the taper: B is linear, A and C are logarithmic curves used where human perception is non-linear, such as volume control.
Rotary potentiometers are continuous analogue devices, unlike rotary encoders, which output digital pulses. If you need absolute position sensing with a simple ADC input, a potentiometer is normally the simpler and cheaper answer.
What to specify
- Total resistance and tolerance
- Pick the resistance from the standard range, then check the tolerance band, which widens at the extremes of the range.
- Taper (A, B or C)
- Linear for measurement and set-point control, logarithmic for audio level and anything judged by ear.
- Gang number
- A single gang for mono or single-axis control, dual gang for stereo channels or two tracks driven by one shaft. Rated power and detent availability differ between them.
- Terminal style and mounting
- Top adjust or side adjust, with or without a sleeve bushing. This decides how the part sits relative to the board and the panel.
- Shaft type and length
- Splined, slotted, knurled and flatted shafts each suit different knobs. Shaft length also constrains whether a bushing can be fitted.
- Detents and rotational life
- A centre detent or 21-step detent gives tactile feedback; a long-life build is available where the control is turned frequently.
Typical applications
- Audio volume, tone, balance and gain controls in amplifiers, mixers, guitar pedals and instrument panels
- Set-point and trim adjustment on industrial controllers, power supplies and test equipment
- Speed, brightness and temperature dials on appliances and professional equipment
- Position and angle reference for joysticks, robotics and motion control assemblies
- Front-panel user controls on medical, laboratory and automotive interior modules
General specifications — F09K series
Values below are the published specifications for our 9 mm square insulated shaft rotary potentiometer. Other sizes and custom builds are quoted case by case.
- 全抵抗値
- 1KΩ ~ 1MΩ
- 全抵抗値許容差
- 500Ω < R < 1MΩ: ±20%; R ≤ 500Ω or R ≥ 1MΩ: ±30%
- 抵抗カーブ
- A, B, C
- 最大使用電圧
- AC 50V / DC 20V
- 定格電力
- 単連: 0.05W; 2連: 0.03W
- 回転雑音
- 100mV 未満
- 絶縁抵抗
- DC 250V 時 100MΩ 超
- 耐電圧
- AC 250V、1分間
- 残留抵抗
- 端子1~2：20Ω未満；端子2~3：20Ω未満
- 連間誤差（2連）
- −40dB ~ 0dB ± 3dB
- 連数
- 単連 (N) / 2連 (G)
- クリック位置
- クリックなし / 中央クリック（単連）/ 21クリック（単連）
- 総回転角度
- 280° ± 10°
- 回転トルク
- 10 ~ 90 gf·cm
- ストッパー強度
- 3.0 Kgf·cm 以上
- 押引強度
- 5.0 Kgf 以上
- クリックトルク
- 30 ~ 120 gf·cm
- 回転寿命
- 標準：15,000回以上；長寿命：100,000回以上
- 使用温度
- −10°C ~ +70°C
Dimensions and construction
- 本体寸法
- 9 mm 角
- 端子とブッシング
- H 上面調整・ブッシングなし / V 側面調整・ブッシングなし / A 上面調整・ブッシングあり / B 側面調整・ブッシングあり
- 高さ H
- 0 該当なし（上面調整）/ 1 = 6.5 mm / 2 = 10.0 mm / 3 = 12.5 mm（側面調整）
- 軸形状
- F / N / C / Y / T / D / P / Q / K 型（スロット、ローレットなど）
- 軸長
- コードにより指定；ブッシングは軸長20 mm超のみ
- 反時計回り端位置
- 軸型に応じて C / A / D、40° ± 10°
Build the exact part number
The F09K page includes a part-number builder that only allows valid option combinations, so the code you send us is one we can manufacture.