THE TRANSFORMER
3 marks · NormalA transformer is used to produce an output voltage of 48 V from a 240 V a.c. mains supply. The primary coil has 960 turns.
Calculate the number of turns needed on the secondary coil to achieve this 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
192 turns (±1)
Common mistakes: Incorrect rearrangement of the formula; Calculation error
Show mark scheme and worked solution
Marking points
M1 · 1 mark · States or uses the transformer equation:
M2 · 1 mark · Rearranges correctly for :
A1 · 1 mark · Substitutes correct values to give turns (allow rounded to nearest integer). (follow-through)
Worked solution
Rearrange for :
Substitute the values: