DC Circuits 7

​Watch this video (2 mins)

Make sure to understand:

• ​What are transducers?

• ​What is the difference between input transducers and output transducers.

Multiple Choice

Which contain only input transducers?

• LED and Lamp

• Loudspeaker and pressure sensors

• Voltmeter and light dependent resistor

• Microphone and Thermistor

Multiple Choice

Which contain only output transducers?

• LED and Lamp

• Loudspeaker and pressure sensors

• Voltmeter and light dependent resistor

• Microphone and Thermistor

Multiple Select

Below are descriptions of several electrical components. Which one of these are input transducers?

Choose more than one.

• Device A converts sound energy to electrical energy

• Device B converts electrical energy to kinetic energy

• Device C converts light energy to electrical energy

• Device D converts heat energy to electrical energy

• Device E converts electrical energy to light energy

​Watch this video (1 min)

Make sure to understand:

• ​What are thermistors?

• ​What is the function of a thermistor?

Multiple Choice

What is the correct symbol for a thermistor?

Multiple Choice

The resistance of a thermistor increases when its temperature increases

• TRUE

• FALSE

​Watch this video (5 mins)

Make sure to understand:

• ​How to calculate output voltage when a potential divider is connected with a thermistor.

Fill in the Blanks

A thermistor has resistance 3900 Ω at 0°C and resistance 1250 Ω at 30°C. The thermistor is connected into the circuit in the picture in order to monitor temperature changes. The battery has an e.m.f. of 1.50 V. The fixed resistor R has a resistance of 7800 Ω. Calculate the output voltage that is measured by the voltmeter when the temperature is at 0°C.

Do not enter the units in your answer.

Fill in the Blanks

A thermistor has resistance 3900 Ω at 0°C and resistance 1250 Ω at 30°C. The thermistor is connected into the circuit in the picture in order to monitor temperature changes. The battery has an e.m.f. of 1.50 V. The fixed resistor R has a resistance of 7800 Ω. Calculate the output voltage that is measured by the voltmeter when the temperature is at 30°C.

Round off your answer to 3 significant figures. Do not enter the units in your answer.

Multiple Choice

When temperature decreases, then the output voltage

• Increases

• Decreases

• Stay the same

Fill in the Blanks

A battery of e.m.f. 4.50 V is connected in series with a fixed resistor of resistance 1200 Ω and a thermistor as shown in the picture. At room temperature, the thermistor has a resistance of 1800 Ω. What is the potential difference across the thermistor.

Do not enter the units in your answer.