Circuit Devices

Question 1

Diode: Describe the current

Answer 1

It lets current flow freely in one direction but not in the other (really high resistance)

Question 2

Diode: What is it made of?

Answer 2

Made from semiconductor s=material such as silicon

Question 3

Diode: What is it used for?

Answer 3

Regulate the potential difference in circuits

Question 4

What does an LED do? What does it stand for?

Answer 4

A light emitting diode emits light when a current flows through it in the forward direction

Question 5

What are LEDs used for? Why?

Answer 5

Lighting: They use a much smaller current than other forms of lighting
Appliances o indicate they are switched on: LEDs indicate the presence of current in a circuit
Digital Clocks, Traffic lights and remote controls

Question 6

What is an LDR?

Answer 6

Light-Dependent Resistor that is dependent on the intensity of light

Question 7

Describe the resistance of an LDR in different brightnesses

Answer 7

In bright light, the resistance falls

In darkness the resistance is highest

Question 8

What are LDRs used for?

Answer 8

Automatic night lights, Outdoor lighting and burglar detectors

Question 9

What is a thermistor?

Answer 9

A temperature dependent resistor

Question 10

Describe the resistance of a thermistor in different conditions

Answer 10

In hot conditions, the resistance drops

In cool conditions, the resistance goes up

Question 11

What are thermistors used for?

Answer 11

Temperature detectors eg. Car engine temperature sensors and electronic thermostats