Chapter SH, Problem 7.1APP

To determine

To calculate: Number of turns in the secondary coil of a step-down transformer.

Answer to Problem 7.1APP

Number of turns in the secondary coil of a step-down transformer is $\underset{\_}{5}$ .

Explanation of Solution

Given:

Input voltage = $900\text{ V}$

Output voltage = $300\text{ V}$

Number of turns in the primary coil = $\text{15}$

Formula used:

Transformer voltage equation is given by,

  $\frac{V_{\text{out}}}{V_{\text{in}}}=\frac{N_2}{N_1}$

Where $V_{\text{out}}$ is output voltage, $V_{\text{in}}$ is input voltage, $N_2$ is number of turns in the secondary coil and $N_1$ is number of turns in the primary coil.

Calculation:

Number of turns in the secondary coil is calculated as:

  $\begin{array}{l}\frac{V_{\text{out}}}{V_{\text{in}}}=\frac{N_2}{N_1}\\ N_2=\frac{V_{\text{out}}\cdot N_1}{V_{\text{in}}}\\ N_2=\frac{\left(300\text{ V}\right)\cdot \left(15\right)}{900\text{ V}}\\ N_2=5\end{array}$

Conclusion:

Number of turns in the secondary coil of a step-down transformer is $\underset{\_}{5}$ .