Question

A model electric train requires 12 V to operate. When connected to a household voltage of 120 V, a transformer is needed. If the primary coil has 250 turns, how many turns must the secondary coil have?

Answer 1

We are given that a transformer is needed to convert 120V into 12V. To determine the number of turns in the secon dary coil we will use the following formula:

`(V_2)/(V_1)=(N_2)/(N_1)`

Where:

`\begin{gathered} V_2=\text{ secondary voltage} \\ V_1=\text{ primary voltage} \\ N_1=\text{ number of turns on primary} \\ N_2=\text{ number of turns on secondary} \end{gathered}`

Now, we plug in the values:

`(12V)/(120V)=(N_2)/(250)`

Now, we multiply both sides