Given the following parameters:

• $V_{OC} = 12 \, \text{V}_{RMS}$
• $R_{int} = 2.5 \, \Omega$
• $R_{load} = 30 \, \Omega$

We can solve the questions step-by-step:

a) Calculate $V_{load}$ (in volts):

First, determine the total resistance in the circuit:

$R_{total} = R_{int} + R_{load} = 2.5 \, \Omega + 30 \, \Omega = 32.5 \, \Omega$

The load voltage $V_{load}$ can be found using the voltage divider formula:

$V_{load} = V_{OC} \times \frac{R_{load}}{R_{total}} = 12 \, \text{V} \times \frac{30 \, \Omega}{32.5 \, \Omega}$

$V_{load} \approx 11.08 \, \text{V}$

b) Calculate $I_{load}$ (in milliamps):

The load current $I_{load}$ can be found using Ohm's law:

$I_{load} = \frac{V_{load}}{R_{load}} = \frac{11.08 \, \text{V}}{30 \, \Omega}$

$I_{load} \approx 0.369 \, \text{A} = 369 \, \text{mA}$

c) Calculate $P_{load}$ (in watts):

The power dissipated across the load can be calculated as:

$P_{load} = V_{load} \times I_{load} = 11.08 \, \text{V} \times 0.369 \, \text{A}$

$P_{load} \approx 4.09 \, \text{W}$

d) Calculate the power required by the primary, $P_{pri}$ (in watts):

The power required by the primary is the total power output, which includes the power dissipated by both $R_{int}$ and $R_{load}$.

First, calculate the total current:

$I_{total} = \frac{V_{OC}}{R_{total}} = \frac{12 \, \text{V}}{32.5 \, \Omega}$

$I_{total} \approx 0.369 \, \text{A}$

The power required by the primary is:

$P_{pri} = V_{OC} \times I_{total} = 12 \, \text{V} \times 0.369 \, \text{A}$

$P_{pri} \approx 4.43 \, \text{W}$

e) Calculate the current into the primary $I_{pri}$ (in milliamps):

We already calculated $I_{total}$ in part (d), which is the same as $I_{pri}$:

$I_{pri} \approx 369 \, \text{mA}$

---

Do you want more details or have any questions?

Here are some related questions you might consider:

1. What would happen if $R_{load}$ increased?
2. How would the circuit be affected if $R_{int}$ were negligible?
3. What is the efficiency of the power transfer from the source to the load?
4. How would the power dissipation change if the load resistance were halved?
5. How could you reduce power losses in $R_{int}$ in practical applications?

Tip: Always account for internal resistances in real circuits when estimating voltages and power efficiency.