*Question T4A01:
Which of the following is an appropriate power supply rating for a typical 50 watt output mobile FM transceiver?*  

*Correct Answer is  D: 13.8 volts at 12 amperes*  

### AI Response: (may contain errors)  

To determine the appropriate power supply rating for a typical 50-watt output mobile FM transceiver, we can use the formula for power:

$$
P = V \times I
$$

where:
- $P$ = power in watts
- $V$ = voltage in volts
- $I$ = current in amperes

### Correct Answer: 13.8 volts at 12 amperes

1. **Why the correct answer is correct:**
   - Using the correct answer, $13.8$ volts and $12$ amperes:
   $$
   P = 13.8 \, \text{V} \times 12 \, \text{A} = 165.6 \, \text{W}
   $$
   - This power rating is sufficient for a 50-watt transceiver, as it provides a good margin for efficiency and additional power needs (like audio output and other functions).

### Why the other choices are incorrect:

2. **Choice A: 24.0 volts at 4 amperes**
   - Calculation:
   $$
   P = 24.0 \, \text{V} \times 4 \, \text{A} = 96.0 \, \text{W}
   $$
   - While this is sufficient power, the voltage is higher than typical for mobile transceivers, which usually operate around 12-14 volts.

3. **Choice B: 13.8 volts at 4 amperes**
   - Calculation:
   $$
   P = 13.8 \, \text{V} \times 4 \, \text{A} = 55.2 \, \text{W}
   $$
   - This power rating is marginally sufficient but does not provide enough current for peak demands, which can exceed 4 amperes during transmission.

4. **Choice C: 24.0 volts at 12 amperes**
   - Calculation:
   $$
   P = 24.0 \, \text{V} \times 12 \, \text{A} = 288.0 \, \text{W}
   $$
   - This option provides excessive voltage for a typical mobile transceiver, which could damage the equipment.

5. **Choice D: 13.8 volts at 12 amperes**
   - This is the correct choice as explained above, providing ample power for the transceiver's needs.

### Summary:
- The ideal power supply for a 50-watt mobile FM transceiver is $13.8$ volts at $12$ amperes, ensuring sufficient power while operating within the typical voltage range for such devices.