10kΩ Linear-Taper Potentiometer
The standard value for feeding a variable analog voltage into a microcontroller input, chosen specifically to balance low current draw against low susceptibility to noise pickup.
How this component works
A potentiometer (often called a "pot") is a three-terminal variable resistor. It contains a resistive track and a conductive wiper that slides along the track when you turn the knob. The resistance between the two outer terminals is fixed, but the resistance between the middle wiper and the outer terminals changes as the wiper moves.
When all three terminals are used, it acts as a variable voltage divider, perfect for volume controls or setting reference voltages. If you only connect the wiper and one outer terminal, it acts as a simple variable resistor (rheostat) to control current.
Deep Dive: 10kΩ Pot (Linear)
The choice of 10kΩ for a sensor-feedback potentiometer comes from a specific tradeoff, not tradition. A typical microcontroller ADC pin presents very high input impedance — often 100MΩ or more — so connecting a 10kΩ pot as a voltage divider to that input loads the divider negligibly; the ADC reads essentially the true wiper voltage rather than a distorted one. At the same time, at 10kΩ the pot only draws about 0.5mA from a 5V supply (V/R = 5V / 10,000Ω), keeping power waste low, while staying low enough in impedance that the wiper wire isn't an easy target for induced electrical noise the way a 1MΩ pot's wiper line would be over any meaningful length.
This entry also uses linear taper deliberately: for a joystick, slider, or angle sensor, the goal is for the output voltage to track the physical position proportionally, so a linear resistance-vs-rotation relationship is exactly what's wanted. That's a genuinely different requirement from the 100kΩ audio pot in this category, where a logarithmic taper is chosen instead to match how humans perceive loudness — swapping the taper type between these two use cases would make either application feel or measure wrong.
Common Use Cases
- Analog sensor/joystick position feedback read by a microcontroller's ADC
- Arduino-style voltage-divider input for tutorials and beginner analogRead() projects
- Manual calibration/trim adjustment in a test or prototype circuit
Frequently Asked Questions
Why is 10kΩ specifically the go-to value for a sensor potentiometer, rather than 1kΩ or 1MΩ?
It's a balance: a microcontroller ADC input typically has very high input impedance (often 100MΩ+), so a 10kΩ pot barely loads it down, keeping the reading accurate. At the same time, 10kΩ draws only a modest current from the supply (V/R = 5V/10kΩ = 0.5mA) without being so high-impedance that stray noise pickup becomes a problem, as an extremely high-value pot might.
Why linear taper instead of logarithmic for a sensor input?
A sensor application usually wants the electrical output to change proportionally with the mechanical rotation or slider position — a linear taper does exactly that. Logarithmic taper deliberately makes the resistance change non-proportionally, which is useful for audio (see the 100kΩ entry) but would distort a position or angle reading.
What happens if I use a 100kΩ pot instead of 10kΩ for an Arduino sensor input?
It would still technically work with a high-impedance ADC input, but it draws less current (less power wasted, if that matters) at the cost of being somewhat more susceptible to noise pickup on the wiper wire, especially over longer wire runs — 10kΩ remains the more forgiving default.
Comparison Notes
Unlike the 100kΩ logarithmic-taper entry in this category, this part's value and linear taper are both chosen for measurement accuracy against a microcontroller ADC, not for matching human perception the way an audio volume pot is.