NEIEP Mechanics Practice Exam

A transformer has 728 turns on the primary winding and 56 turns on the secondary. With 120 volts applied to the primary, what is the output voltage on the secondary?

1. 4.25 volts

2. 9.23 volts

3. 16.5 volts

4. 24 volts

The correct answer is: 9.23 volts

To determine the output voltage of the secondary winding in a transformer, you can use the transformer turns ratio formula given by: \[ \frac{V_p}{V_s} = \frac{N_p}{N_s} \] Where: - \(V_p\) = voltage applied to the primary winding - \(V_s\) = voltage output from the secondary winding - \(N_p\) = number of turns in the primary winding - \(N_s\) = number of turns in the secondary winding In this case: - \(N_p = 728\) turns - \(N_s = 56\) turns - \(V_p = 120\) volts First, find the turns ratio: \[ \frac{N_p}{N_s} = \frac{728}{56} = 13 \] This means that for every 13 turns on the primary, there is 1 turn on the secondary. To calculate the output voltage, rearrange the formula to solve for \(V_s\): \[ V_s = \frac{V_p}{\frac{N_p}{N_s}} = \frac{120 \text{ volts}}{13} \