Potentiometers Selection Guide
A potentiometer is a three-terminal voltage divider; it comes in analog and digital types, and for analog, resistance, number of turns and wiring decide the choice.
This guide covers the points to look at when choosing products in the Potentiometers category.
Potentiometer types
- Analog potentiometers: These are models that fit into a 22 mm hole in the panel door, with a shaft turned by hand. The product data includes resistance values such as 1 kΩ, 2.2 kΩ, 5 kΩ, 10 kΩ and 100 kΩ, and single-turn and multi-turn types. EMAS product names list a 1.5 W power rating together with a 40 °C or 70 °C temperature rating.
- Digital potentiometers: These are panel devices that show the set value on a display. The Enda EDP series is listed with 230 V AC or 10-30 V DC / 8-24 V AC supply, with RS485 Modbus communication and without communication. The GEMO DP102 and Tense PTM-01 and PTM-02 models have a 0-10 V or 4-20 mA output.
Resistance, number of turns and wiring on an analog potentiometer
A potentiometer is a three-terminal voltage divider. In speed setting, one of the outer terminals is connected to the reference voltage output of the drive, the other to the analog common terminal, and the center terminal (wiper), which moves with the shaft, to the analog input.
- Resistance value. A low-resistance potentiometer draws more current from the reference source. With a high-resistance potentiometer, on the other hand, the internal resistance of the analog input pulls the output voltage away from the expected value. For this reason, the value or range given in the drive manual is used as the basis.
- Number of turns. In a single-turn model, the wiper sweeps the whole range in slightly less than one full turn. In a multi-turn model, the same range is spread over several turns; fine adjustment becomes easier and quick changes become harder. The EMAS H Series is multi-turn and the C Series is single-turn.
- Mounting and protection. The 22 mm hole is the same size as for push buttons and pilot lights on the panel door. EMAS product names state IP65.
- Signal cable. If the potentiometer will be mounted away from the panel, the cable type and length limit in the drive manual are used as the basis. You can find the difference between shielded and unshielded control cables in the article LIYY and LIYCY cable difference.
The drives these potentiometers connect to are in the variable frequency drives category.
When to choose a digital potentiometer
- If the value needs to be seen and repeated. The setting is read as a number; it is easy to return to the same value.
- If the signal will be carried over a distance. The accuracy of a 4-20 mA current signal is not affected by the voltage drop in the connecting conductors; for this reason a current-output model is preferred on long runs.
- If the setting will also be changed remotely. Enda models with RS485 Modbus connect to the communication line; the Tense PTM product data lists control through digital inputs and an analog output.
- If the setting needs to be limited. The Tense PTM product data includes lower and upper limits for the set value, a password-protected menu and a ramp function; the limit and the password are meant to prevent the operator from going outside the permitted range.
A digital model requires a supply voltage and, instead of a 22 mm hole, a panel cutout suited to its housing; the product data includes 72 × 72 mm and 77 × 35 mm housings.
Brands in this category
- Enda: digital potentiometers with codes EDP7041 and EDP2041.
- EMAS: 22 mm potentiometers, C Series single-turn and H Series multi-turn.
- Tense: 5 kΩ and 10 kΩ analog models with code WL9 PT, digital models with code PTM.
- Isıso: 22 mm potentiometers with code LA42DWQ; 2.5 kΩ, 5 kΩ and 10 kΩ.
- GEMO: digital potentiometers with code DP102, with 0-10 V or 4-20 mA output.
- Gwest and Konsan: 22 mm single-turn potentiometers in 5 kΩ and 10 kΩ values.
Ordering notes
- Potentiometers are sold by the piece. The abbreviations 5K and 10K in product names indicate a resistance value of 5 kΩ and 10 kΩ.
- An analog potentiometer is a passive element that needs no supply voltage; confirm from the manufacturer data what the 220 V mention in Gwest and Konsan product names means.
- The manufacturer code is recorded in the product name or in the stock code (for example EDP7041-230, DP102-V-230VAC, LA42DWQ-22-10K); you can type the code into the search box.
Comparison and selection table
| Selection Criterion | Ø22 mm Monoblock Panel Potentiometer | Multi-Turn Precision Potentiometer | Chassis-Mount Rotary Potentiometer + Dial Knob |
|---|---|---|---|
| Mounting & Design | Fits directly into standard Ø22.5 mm pushbutton hole | 3, 5 or 10-turn wirewound element + counting dial knob | Bushing-mount shaft pot + separate graduated pointer knob |
| Resistance Values | 1 kΩ, 2.2 kΩ, 4.7 kΩ, 5 kΩ, 10 kΩ (standard VFD input) | 1 kΩ, 5 kΩ, 10 kΩ with tight linearity tolerance | 1 kΩ – 1 MΩ (Linear taper B or Audio taper A) |
| Front Protection | IP65 / IP66 dust-tight and water-jet resistant bezel | Lockable turns-counting dial for repeatable setpoints | IP20 / IP40 indoor control desk mounting |
| Typical Application | Variable frequency drive (VFD) 0–10 V speed reference | Precision dosing, tension control & fine speed trimming | OEM control boards, dimmers, amplifiers & test rigs |
Frequently asked questions
How many kΩ potentiometer should be connected to a frequency inverter?
The value is given in the analog input section of the drive manual and varies by brand. Very low resistance may draw more current from the drive's reference voltage output than allowed; very high resistance pulls the output voltage off because of the internal resistance of the analog input. Values such as 1 kΩ, 5 kΩ and 10 kΩ are listed in this category; choose the value stated in the manual or one within the stated range.
How are the three terminals of a potentiometer connected?
The two outer terminals are the ends of the resistive element, and the middle terminal is the wiper that travels along the element as the shaft is turned. In speed setting, one of the outer terminals is connected to the reference voltage output of the drive, the other to the analog common terminal, and the wiper to the analog input. If the outer terminals are swapped, increase and decrease are reversed relative to the direction of shaft rotation. For terminal designations, the wiring diagram in the drive manual is used as the basis.
What is the difference between a single-turn and a multi-turn potentiometer?
In a single-turn model, the wiper sweeps the whole resistance range in slightly less than one full turn; adjustment is quick. In a multi-turn model, the same range is spread over several turns, so turning the shaft by the same angle changes the value much less and fine adjustment is possible. A single-turn model suits places where the value is changed often and roughly, and a multi-turn model suits places where precise settings are rarely changed.
Should a digital potentiometer have a 0-10 V or a 4-20 mA output?
First look at the analog input of the device that will receive the signal: if the input is voltage type, a 0-10 V model is needed; if it is current type, a 4-20 mA output model is needed. If the input can be set to either type, distance decides. The accuracy of a current signal is not affected by the voltage drop in the connecting conductors, so 4-20 mA is preferred on long runs. 0-10 V is mostly used for short connections inside the panel.
Can a digital potentiometer be used in place of an analog potentiometer?
It can, if the analog input of the drive accepts a 0-10 V or 4-20 mA signal; use the drive manual for the input setting. The wiring is different: a digital potentiometer does not take its reference voltage from the drive, it works from its own supply, and only the signal output and the common terminal are connected to the analog input. Instead of the 22 mm hole in the panel door, a cutout suited to the device's housing has to be made.