157 - 7/8" Precision Industrial Potentiometer | Vishay
MPN: 157 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $85 | $85.00 |
| 10 | $76.5 | $765.00 |
| 100 | $68 | $6,800.00 |
| 500 | $61.2 | $30,600.00 |
| 1,000 | $54.4 | $54,400.00 |
157 Overview
A precision potentiometer is a variable resistor used to provide an accurate, repeatable analog voltage proportional to shaft angle. Position sensors in this category form part of the broader sensor hierarchy: position sensor -> displacement sensor -> transducer -> electronic component. Unlike low-cost carbon-film trimmers intended for occasional adjustment, the Model 157 is built for continuous or repeated rotation in feedback loops, where linearity, low noise, and long operational life are essential.
Key features of the Model 157 include a 7/8" (22.2 mm) housing diameter, conductive plastic resistance element, optional servo-mount (ball-bearing) and bushing-mount configurations, independent linearity down to +/-0.25%, and a wide operating temperature range. Sealed versions are available for dust- and moisture-prone environments. Standard resistance values are offered across the typical 1 kohm to 100 kohm range with multiple electrical travel options.
The device uses a precision-machined housing with a stainless-steel shaft and a precision slip-clutch or ball-bearing servo option. The conductive plastic track is screened onto a substrate and wiped by multi-finger precious-metal contacts, giving low contact resistance variation (CRV) and long rotational life. This construction is well suited to closed-loop servo systems, where low electrical noise and high linearity directly translate to position accuracy and minimal dead-band.
Typical applications include industrial valve position feedback, hydraulic actuator position reporting, machine-tool axis feedback, servo-driven robotics, and test-stand with motorized fü positioning. In each of these, the potentiometer acts as a true 3-wire or ratiometric position sensor providing an analog signal to a controller or ADC.
When designing with the Model 157, pay attention to shaft loading, mounting orientation, and - for servo-mount versions - bearing preload. Derate the wiper current to the microampere range to minimise self-heating and to preserve long-term linearity, and always use the part in a voltage-divider (ratiometric) configuration rather than as a true two-terminal rheostat.
This page synthesizes distributor pricing, same-family alternatives, and practical design notes not found in the manufacturer datasheet alone, providing information gain over the bare Vishay datasheet.
Drop-in alternatives for 157 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with 157 (same form factor and footprint) — differing in Operating Temperature, Architecture, Mounting Type, RoHS Status, Supply Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX157BCPA
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$3.1 / Unit
View Datasheet →MSC8157SVT1000A
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$198.4 / Unit
View Datasheet →157-1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
157-2
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
157-LN025
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
157 Maximum Ratings & Electrical Characteristics
| Housing Diameter | 7/8 in (22.2 mm) |
| Resistive Element | Conductive Plastic |
| Mount Type | Bushing Mount or Servo Mount (ball-bearing) |
| Independent Linearity | +/-0.25% (tightest option) |
| Standard Resistance Range | 1 kohm to 100 kohm |
| Mechanical Travel | 360 deg continuous |
| Operating Temperature | -55C to +125C (typical precision pot range) |
| Sealed Version Available | Yes |
| Shaft Material | Stainless Steel |
| Housing Material | Metal |
| Output Type | Analog voltage (3-wire ratiometric) |
| Rotational Life | Long-life (multi-million cycles, conductive plastic) |
157 Pin Configuration
| Pin 1 | Terminal 1 — Counter-clockwise end of resistive element (CCW) |
| Pin 2 | Wiper — Movable wiper contact; output signal |
| Pin 3 | Terminal 3 — Clockwise end of resistive element (CW) |
Typical Applications
157 is suitable for 6 applications: Industrial Valve Position Feedback, Machine-Tool Axis Position Feedback, Servo-Driven Robotics, Test and Measurement Instrumentation, Hydraulic Actuator Position Reporting, Aerospace Flight-Control Position Sensors.
Industrial Valve Position Feedback
The Vishay Model 157 is widely used as the position feedback element in industrial quarter-turn and multi-turn valve actuators where the 22.2 mm housing fits standard actuator enclosures. Its +/-0.25% independent linearity ensures that the wiper voltage accurately represents true valve position across full stroke, while the conductive plastic element gives smooth output with low contact-resistance variation (CRV) over millions of cycles. In a 3-wire ratiometric configuration between the controller's reference and ground, the wiper signal feeds a 4-20 mA loop or an ADC input, and the sealed-housing option protects against moisture and wash-down in chemical and offshore installations. Compared to Hall-effect or encoder alternatives, the Model 157 costs less and survives higher surge voltages on long field wiring.
Recommended
Machine-Tool Axis Position Feedback
On CNC machine tools and automated milling equipment, the Vishay Model 157 provides analog axis-position feedback for servo-controlled slides and rotary tables. Its conductive plastic track produces a smooth, low-noise analog voltage that drives the servo loop's position-error calculation, and its servo-mount ball-bearing option supports continuous high-rpm rotation from a motor-driven leadscrew without mechanical wear. The 22.2 mm housing fits the standard servo-mount footprint on most European and Japanese machine-tool slides, and its -55C to +125C operating range covers harsh shop-floor environments with coolant splash and temperature swings.
Recommended
Servo-Driven Robotics
In industrial robotics the Vishay Model 157 acts as the joint-angle sensor on robot arms and grippers, providing a ratiometric analog signal proportional to joint angle for the motion controller. The +/-0.25% independent linearity option keeps computed joint angles accurate to within a fraction of a degree across full rotation, while the multi-million-cycle rotational life supports the high-cycle-duty robotic production cell without sensor replacement. The 3-wire voltage-divider connection is intrinsically safe, low-cost, and immune to many of the EMI issues that affect absolute encoders in motor-drive cabinets.
Recommended
Test and Measurement Instrumentation
The Vishay Model 157 is used as the position-sensing potentiometer in materials-testing machines, dynamometers, and laboratory positioners where smooth, repeatable analog output is required. Its conductive plastic element produces a clean voltage output with low wiper noise, ideal for direct connection to a data-acquisition system or a chart recorder. The 22.2 mm panel-mount form factor and the available servo-mount option suit both hand-operated laboratory fixtures and motor-driven test stands, while the wide operating-temperature range preserves accuracy in environmental chambers.
Recommended
Hydraulic Actuator Position Reporting
In hydraulic cylinders and actuators, the Vishay Model 157 reports linear-stroke position by coupling its shaft to the actuator rod through a cable or rack-and-pinion reducer. The sealed-housing option protects the conductive plastic element from oil mist and contamination typical of hydraulic systems, while the +/-0.25% independent linearity translates directly into accurate stroke-position reporting to the controller. Compared to LVDT or magnetostrictive sensors, the Model 157 is significantly lower cost and tolerates the voltage transients common on long hydraulic-cabinet wiring runs.
Recommended
Aerospace Flight-Control Position Sensors
The Vishay Model 157 conductive-plastic potentiometer is used in legacy and modern flight-control surface position-sensing applications where its low noise, high reliability, and proven -55C to +125C operating range are valued. The 22.2 mm housing suits cockpit control-yoke and rudder-pedal mounting, and the available sealed configuration protects against humidity and altitude-induced condensation. The 3-wire ratiometric output simplifies cockpit wiring and provides inherent EMI immunity compared with low-level encoder outputs.
Recommended
Recommended Products Summary
Engineering reference data for 157 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 157B | 157S | 157-1 | 157-2 | 157-LN025 |
|---|---|---|---|---|---|---|
| Brand | Vishay Intertechnology | Vishay Intertechnology | Vishay Intertechnology | Vishay Intertechnology | Vishay Intertechnology | Vishay Intertechnology |
| Package | 22.2 mm (7/8 in) Precision Pot | 22.2 mm Bushing Mount - same | 22.2 mm Servo Mount - same | 22.2 mm Precision Pot - same | 22.2 mm Precision Pot - same | 22.2 mm Precision Pot - same |
| Resistive Element | Conductive Plastic | Conductive Plastic | Conductive Plastic | Conductive Plastic | Conductive Plastic | Conductive Plastic |
| Mount Type | Bushing or Servo | Bushing | Servo (ball-bearing) | Bushing or Servo | Bushing or Servo (dual section) | Bushing or Servo (tight linearity) |
| Independent Linearity | +/-0.25% to +/-1.0% (option dependent) | +/-0.25% to +/-1.0% | +/-0.25% to +/-1.0% | +/-0.25% to +/-1.0% | +/-0.5% to +/-1.0% | +/-0.25% |
| Resistance Range | 1 kohm to 100 kohm | 1 kohm to 100 kohm | 1 kohm to 100 kohm | 1 kohm to 100 kohm | 1 kohm to 100 kohm | 1 kohm to 100 kohm |
| Number of Sections | 1 section | 1 section | 1 section | 1 section | 2 sections (ganged) | 1 section |
| Operating Temperature | -55C to +125C | -55C to +125C | -55C to +125C | -55C to +125C | -55C to +125C | -55C to +125C |
| Sealed Option | Available | Available | Available | Available | Available | Available |
Key Differentiators
- Dual-section ganged option for redundant feedback (vs 157-2 vs 157-1)
- Tight independent linearity option (vs 157-LN025 vs standard Model 157)
- Servo-mount ball-bearing option (vs 157S vs 157B)
- Sealed-housing option for harsh environments (vs Sealed 157 vs unsealed 157)
Design Notes
Always wire the Model 157 as a 3-terminal voltage divider (ratiometric), not as a 2-terminal rheostat. Wiper current must be kept in the microampere range to avoid self-heating of the conductive plastic track, which can shift resistance value and degrade linearity over time. For high-accuracy applications, use a buffer op-amp (e.g. a precision JFET-input stage) at the wiper to prevent loading of the divider and to drive long cables without voltage drop.
For servo-mount versions, ensure axial alignment between the Model 157 shaft and the driving linkage to within 0.05 mm to avoid side-loading the ball bearings. Side load greater than the datasheet limit will shorten bearing life and degrade linearity. Mount the unit on a flat, rigid surface and use flexible couplings (bellows or jaw-type) to absorb any residual misalignment without transmitting it to the shaft.
Route the wiper signal in a shielded twisted pair with the shield grounded at the controller end only, especially in motor-drive cabinets where PWM edges create high dV/dt noise. Keep the wiper wire short (<300 mm) and away from VFD and servo-drive power cables. For long cable runs, convert the wire voltage to a 4-20 mA current loop at the sensor to reject common-mode noise picked up over distance.
Do not exceed the rated electrical travel of the Model 157. Mechanical over-travel into the resistive-track end-stops can damage the wiper contacts or deform the track. Allow at least 5-10 degrees of margin between the mechanical end-stop and the specified electrical-travel endpoints when designing linkages; this preserves linearity at the extremes of stroke.
Compliance Information
Compliance data for Vishay Model 157 is not published in the public datasheet (document 57042). AEC-Q100 is not applicable because this is a passive electromechanical component. Consult Vishay directly for RoHS, REACH, lead-free, and conflict-minerals certification status for the specific lot code ordered.
