Rheostat
A variable resistor with two terminals — the fixed end and the wiper. Turning the wiper adjusts how much resistance is in the circuit, making it useful for dimmer controls, motor speed adjustment, and manual gain tuning.
Properties
| Property | Description | Default | Range |
|---|---|---|---|
| Resistance | Maximum end-to-end resistance (Ω) | 10 000 Ω | 1 Ω – 1 MΩ |
| Power rating | Maximum continuous dissipation (W) | 1 W | 0.25 W – 50 W |
| Wiper position | Fraction of total resistance in use (0 = minimum, 1 = maximum) | 0.5 | 0.00 – 1.00 |
Simulation behavior
The effective resistance is wiper_position × max_resistance. During simulation you can drag the wiper slider in the component properties panel to change resistance in real time — the circuit updates instantly without stopping the simulation.
Power is calculated against the effective resistance at the current wiper position. If dissipation exceeds the power rating at any position, the component fails open.
Tips
- Set wiper position to 0.01 rather than 0 to avoid a near-short condition when the full supply voltage is across a very small resistance.
- Combine a rheostat with an ammeter to observe how current changes linearly as you move the wiper.
- For precision voltage division use a potentiometer model (three-terminal) instead; the rheostat only exposes two terminals.