USING TRANSFORMERS TO CHANGE VOLTAGES
3 marks · EasyA transformer used for a phone charger has 500 turns on its primary coil and 100 turns on its secondary coil. The input voltage is 230 V.
Is this transformer step-up or step-down? State why.
Calculate the output voltage.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Step-down, because the secondary coil has fewer turns than the primary
(b) 46 V
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies as a step-down transformer and justifies answer.
M1 (b) · 1 mark · Uses transformer equation:
A1 (b) · 1 mark · Gives output voltage V (accept 45-47 V).
Worked solution
a) This is a step-down transformer because there are fewer turns on the secondary coil than the primary.