Question 4
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explain the following:
- Command.
- Controlled variable.
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Classify the following devices into open loop or closed loop control systems.
- Gas cooker
- Microwave oven
- Bathroom water heater
- Deep freezer
- Stopwatch
- Soldering iron
Observation
The Chief Examiner reported that majority of the candidates could not recall the relationship between the various d.c. current flows in a bipolar junction transistor.
The expected responses were:
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- Command refers to the reference or input signal
- Controlled variable indicates output signal,
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Classification into open loop and closed loop control systems
Open loop control system Closed loop control system Closed loop control system Gas cooker Deep freezer Microwave oven Bathroom water heater Stopwatch Soldering iron