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.
- Полное сопротивление
- 1KΩ ~ 1MΩ
- Допуск полного сопротивления
- 500Ω < R < 1МΩ: ±20%; R ≤ 500Ω или R ≥ 1МΩ: ±30%
- Функциональная характеристика сопротивления
- A, B, C
- Макс. рабочее напряжение
- AC 50В / DC 20В
- Номинальная мощность
- Одинарный блок: 0,05Вт; сдвоенный блок: 0,03Вт
- Шум вращения
- Менее 100мВ
- Сопротивление изоляции
- Более 100МΩ при DC 250В
- Электрическая прочность
- 1 минута при AC 250В
- Остаточное сопротивление
- Выводы 1~2: менее 20Ω; выводы 2~3: менее 20Ω
- Погрешность согласования (сдвоенный блок)
- −40дБ ~ 0дБ ± 3дБ
- Количество секций
- Одинарная секция (N) / сдвоенная секция (G)
- Опция фиксатора
- Без фиксатора / центральный фиксатор (одинарная секция) / 21 фиксация (одинарная секция)
- Полный угол поворота
- 280° ± 10°
- Момент вращения
- 10 ~ 90 гс·см
- Прочность упора
- 3,0 Кгс·см мин.
- Усилие на нажатие-вытягивание
- 5,0 Кгс мин.
- Момент щелчка
- 30 ~ 120 гс·см
- Срок службы при вращении
- Стандарт: мин. 15 000 циклов; увеличенный срок службы: мин. 100 000 циклов
- Диапазон рабочих температур
- −10°C ~ +70°C
Dimensions and construction
- Размер корпуса
- 9 мм квадрат
- Вывод и втулка
- H верхняя регулировка без втулки / V боковая регулировка без втулки / A верхняя регулировка с втулкой-гильзой / B боковая регулировка с втулкой-гильзой
- Высота (H)
- 0 = не применяется (только верхняя регулировка), 1 = 6,5 мм, 2 = 10,0 мм, 3 = 12,5 мм (только боковая регулировка)
- Тип вала
- Типы F / N / C / Y / T / D / P / Q / K (шлицевой, со шлицем, рифлёный и другие)
- Длина вала
- Определяется кодом; втулка доступна только при длине вала более 20 мм
- Положение полного поворота против часовой стрелки
- Группа C / A / D в зависимости от типа вала, 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.