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Sensors and Transducers module quiz: LDR and thermistor, switch inputs, output transducers and the relay (O-Level Electronics) quiz

12questions. Pick an answer and you'll see why right away.

  1. How does the resistance of a light-dependent resistor (LDR) change with light?

  2. How does the resistance of a typical thermistor change as it gets hotter?

  3. What is the purpose of a pull-down resistor with a push switch used as a logic input?

  4. Which energy conversion does a loudspeaker perform?

  5. Which energy conversion does an electric motor perform?

  6. Why is a relay used to switch a mains-powered load from a low-voltage circuit?

  7. Why is a flyback (protective) diode connected across a relay coil?

  8. An LDR is placed at the bottom of a potential divider with a fixed resistor on top. As it gets darker, what happens to the output voltage taken across the LDR?

  9. Which of these is an input transducer?

  10. What does a potentiometer (variable resistor used as a divider) provide as an input?

  11. Which output transducer converts electrical energy to light?

  12. A thermistor is used to switch on a cooling fan when it gets hot. As the temperature rises, what does the thermistor resistance do?