DT Y8 EOY exam

Question 1

What is the function of a 9V battery?

Answer 1

To store electrical energy and to power something.

Acts as a power supply in the circuit.

Question 2

What is the purpose of the switch SW1 in the circuit?

Answer 2

To control the flow of electrical current by making or breaking it.

It is a latching switch that turns the alarm on and off.

Question 3

What does the 330Ω resistor (R3) do in the circuit?

Answer 3

Controls/limits the amount of current going through the circuit.

Protects the LED D1 from too much current.

Question 4

What is the function of an LED?

Answer 4

Acts as a valve allowing current to flow in one direction and emits light when current flows correctly.

The LED in the circuit shows visual confirmation of sufficient power and is polarised.

Question 5

What is the purpose of resistor R1 (18kΩ) in the circuit?

Answer 5

To massively reduce the amount of current travelling to the pressure pad.

Resistors are used to control/limit current in circuits.

Question 6

Fill in the blank: The function of a switch is to _______ the flow of an electrical current.

Answer 6

control

Question 7

True or False: The LED only allows current to flow in both directions.

Answer 7

False

Question 8

Fill in the blank: The purpose of the LED in the circuit is to show a _______ confirmation that the circuit has sufficient power.

Answer 8

visual

Question 9

What does the term ‘polarised’ mean in relation to the LED?

Answer 9

It means the LED only allows current to flow in one direction.