*Question G5C02:
What is the output voltage if an input signal is applied to the secondary winding of a 4:1 voltage step-down transformer instead of the primary winding?*  

*Correct Answer is  A: The input voltage is multiplied by 4*  

### AI Response: (may contain errors)  

To understand the behavior of a 4:1 voltage step-down transformer when an input signal is applied to the secondary winding instead of the primary, we need to consider the basic principles of transformer operation.

### Correct Answer Explanation:
- **Correct Answer: A: The input voltage is multiplied by 4.**
  
  In a transformer, the voltage ratio is determined by the turns ratio. For a 4:1 transformer:
  
  $$ \frac{V_p}{V_s} = \frac{N_p}{N_s} = 4 $$
  
  where:
  - $V_p$ = primary voltage
  - $V_s$ = secondary voltage
  - $N_p$ = number of turns in the primary winding
  - $N_s$ = number of turns in the secondary winding

  If you apply a voltage to the secondary winding, the voltage on the primary will be 4 times that of the secondary. Thus, if you apply an input voltage $V_s$ to the secondary, the output voltage $V_p$ on the primary will be:

  $$ V_p = 4 \times V_s $$

### Incorrect Answer Explanations:
- **B: The input voltage is divided by 4.**
  
  This is incorrect because applying a voltage to the secondary does not divide it; instead, it multiplies the voltage on the primary side by the turns ratio.

- **C: Additional resistance must be added in series with the primary to prevent overload.**
  
  This is not necessary in this context. The transformer will adjust the current based on the load on the secondary side, and adding resistance in series is not a standard practice for preventing overload in this scenario.

- **D: Additional resistance must be added in parallel with the secondary to prevent overload.**
  
  Similar to option C, this is not required. The transformer will handle the load based on its design, and adding parallel resistance is not a typical solution for overload issues.

### Summary:
- A 4:1 transformer increases the voltage on the primary side when a voltage is applied to the secondary.
- The relationship between primary and secondary voltages is governed by the turns ratio.
- No additional resistances are needed for overload protection in this context.

This understanding is crucial for the Extra Class exam, as it demonstrates knowledge of transformer operation and electrical principles.