To find the Norton equivalent circuit from a given circuit, I like to follow some clear steps. Here’s what I usually do:

1. Identify the Part of the Circuit

First, I decide which part of the circuit I want to simplify. This usually means finding the points where we want to look closer, called terminals. I mark these as terminals A and B.

2. Remove the Load Resistor

If there is a load resistor connected between terminals A and B, I take it out for now. The Norton equivalent will replace this resistor with a current source and a parallel resistor.

3. Find the Norton Current ($I_N$)

Next, I need to find the Norton current. This is the current that would flow if we connected a wire across terminals A and B. To do this:

• I connect a short wire across the terminals.
• Then, I calculate the current ($I_N$) that flows through this wire. I can use methods like mesh analysis or nodal analysis, or just apply Ohm’s Law where needed.

4. Find the Norton Resistance ($R_N$)

After getting the current, the next step is to find the Norton resistance. Here’s how:

• I turn off all independent sources in the circuit. This means I replace voltage sources with wires (short circuits) and current sources with breaks (open circuits).
• Then, I look again at terminals A and B to find the equivalent resistance. I can often figure this out by combining resistors in series and parallel.

5. Create the Norton Equivalent Circuit

Now that I have both $I_N$ and $R_N$, it’s time to put the Norton equivalent together:

• I draw a current source with the value of $I_N$.
• I place the Norton resistance $R_N$ in parallel with that current source. This model shows the original circuit as viewed from terminals A and B.

6. Reconnect the Load Resistor

Finally, if I removed a load resistor in step 2, I put it back across terminals A and B in the Norton equivalent.

Summary

So, to sum it up, here are the key steps to find the Norton equivalent circuit:

1. Identify the part of the circuit.
2. Remove the load resistor.
3. Find the Norton current by shorting the terminals.
4. Find the Norton resistance by turning off sources and calculating the equivalent resistance.
5. Create the Norton equivalent circuit using $I_N$ and $R_N$.
6. Reconnect the load resistor.

Following these steps makes it easier for me to simplify complicated circuits!