Question

The "power cube" transformer for a portable CD player has an output of 6.9 V and 600 mA (both rms) when plugged into a 120 V outlet.a. If the primary coil has 400 turns of wire, how many turns are on the secondary coil?b. What is the peak current in the primary coil?

Answer 1

23

0.04879 A

Step-by-step explanation:

T denotes turns

V denotes voltage

p denotes primary

s denotes secondary

For turns

`(T_s)/(T_p)=(V_s)/(V_p)\\\Rightarrow T_s=(V_s)/(V_p)* T_p\\\Rightarrow T_s=(6.9)/(120)* 400\\\Rightarrow T_s=23`

The number of turns in the secondary coil is 23

For current

`(T_s)/(T_p)=(I_p)/(I_s)\\\Rightarrow (23)/(400)=(I_p)/(0.6)\\\Rightarrow I_p=(23)/(400)* 0.6\\\Rightarrow I_p=0.0345\ A`

The peak current in the primary coil would be

`\sqrt2* 0.0345=0.04879\ A`