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Electronic and control systems
Quick questions on Input sensors and the voltage divider - CCEA GCSE Technology and Design
8short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What are switches as inputs?Show answer
The simplest input is a switch, which is either open (no current) or closed (current flows). Push-to-make switches, toggle switches, reed switches (operated by a magnet) and tilt switches all provide a clear on/off input to a system.
What are sensors?Show answer
These sensors do not directly give a voltage - they change resistance. To make a useful signal, the change in resistance must be turned into a change in voltage, which is what the voltage divider does.
What is the voltage divider?Show answer
If one of the resistors is a sensor (an LDR or thermistor), its changing resistance changes how the voltage is shared, so the output voltage changes with light or temperature. That changing voltage is the signal passed to the process stage.
What is q1?Show answer
How does the resistance of an LDR change as it gets darker? [1 mark]
What is q2?Show answer
What does a thermistor sense? [1 mark]
What is q3?Show answer
What is a voltage divider used for in an input subsystem? [2 marks]
What is q4?Show answer
In a voltage divider across 9 V, 4 V appears across one resistor. What is the voltage across the other? [1 mark]
What is q5?Show answer
Give one use of a reed switch as an input. [1 mark]