In a step-up transformer, in comparison with the secondary the primary coil has __

Options

A. less voltage and high current
B. high voltage and less current
C. less voltage and less current
D. high voltage and high current

Answer

**Step-by-Step Solution:**

1. **Understanding the Transformer:**
A transformer consists of two coils: the primary coil and the secondary coil. The primary coil is connected to the input voltage source, while the secondary coil delivers the output voltage.

2. **Step-Up Transformer Definition:**
In a step-up transformer, the voltage in the secondary coil is greater than the voltage in the primary coil. This means that the transformer increases the voltage from the primary to the secondary side.

3. **Turn Ratio:**
The relationship between the primary and secondary voltages and the number of turns in the coils is given by the formula:
\[ \frac{V_s}{V_p} = \frac{N_s}{N_p} \]
where \( V_s \) is the secondary voltage, \( V_p \) is the primary voltage, \( N_s \) is the number of turns in the secondary coil, and \( N_p \) is the number of turns in the primary coil.

4. **Analyzing a Step-Up Transformer:**
Since the secondary voltage is greater than the primary voltage in a step-up transformer, it follows that:
\[ N_s > N_p \]
This means the number of turns in the secondary coil is greater than the number of turns in the primary coil.

5. **Conclusion:**
Therefore, in comparison with the secondary coil, the primary coil has fewer turns.

**Final Answer:**
In a step-up transformer, in comparison with the secondary, the primary coil has fewer turns.

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