The following diagram shows a computer-controlled central heating system. (a) State the purpose of the ADC in this system. [2] (b) Explain why this system u...
Question 1 Report
The following diagram shows a computer-controlled central heating system.
(a) State the purpose of the ADC in this system. [2]
(b) Explain why this system uses feedback. [2]
(c) State one actuator shown in the diagram and describe its role. [2]
Answer Details
(a) The ADC (analogue-to-digital converter) converts the analogue signal produced by the temperature sensor [1] into a digital value that the microprocessor can process. [1] Temperature is a continuous physical quantity, and the sensor produces an analogue electrical signal. Since the microprocessor can only work with digital data (binary numbers), the ADC performs this essential conversion.
(b) Feedback is used so the system can continuously monitor the actual temperature of the room. [1] By feeding the current temperature reading back to the microprocessor, the system can compare it against the desired temperature and automatically adjust the heater or fan output to maintain the correct temperature without human intervention. [1] Without feedback, the system would have no way of knowing whether its actions were having the intended effect.
(c) The heater/fan shown in the diagram is an actuator. [1] Its role is to physically change the environment by heating the air (when the temperature is too low) or cooling it with the fan (when the temperature is too high), in direct response to control signals from the microprocessor. [1]
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