- 2081 Bhadra · 4 marks
Feedback vs non-feedback control systems
Short answer
Non-feedback (open loop) acts without output measurement; transfer function G(s); accuracy depends on calibration; no disturbance rejection; usually stable. Feedback (closed loop) uses output feedback, transfer function G/(1+GH); high accuracy; disturbance reduced by (1+GH); faster but can become unstable; complex and costly.
Differentiate between feedback and non-feedback control systems.
A non-feedback (open-loop) system acts only on the input; a feedback (closed-loop) system also measures the output and acts on the error.
| Point | Non-feedback (open loop) | Feedback (closed loop) |
|---|---|---|
| Control action | independent of output | depends on output error |
| Transfer function | ||
| Accuracy | depends on calibration | high, self-correcting |
| Sensitivity to | ||
| Disturbance effect | full | reduced by |
| Speed (time constant) | , faster | |
| Stability | usually stable | can become unstable |
| Gain | higher | reduced |
| Cost, components | simple, cheap | complex, costly |
| Example | toaster, timer traffic light | AC with thermostat, motor speed control |
✓ Answer checked by Claude Opus 5.5 (high effort)
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