• Convert between these two using the VIR triangle (R is shared between the two)
• If there are only independent sources, calculate $V_{oc}$ or $I_{sc}$ then find $R$ by applying a test source
• If both are present, calculate $V_{oc}$ and $I_{sc}$
• If only dependent is present, $V_{oc}=I_{sc}=0$, then apply a test source
• The thing you're replacing must be linear
• Dependent variables must be from within the circuit you're replacing
• If you see something that can be replaced by a Thévenin or Norton equivalent circuit, you can replace it with the opposite kind of source, to make the circuit completely voltage source, or completely current sources (do not transform the thing with the value you're trying to find in it)
  • This is applicable to dependent sources too

Thévenin Equivalent Circuits

• If you have some linear circuit that contains only resistors, dependent, and independent sources, you can turn it into a circuit with an independent voltage source $V_{th}$ in series with a resistor $R_{th}$

How to Calculate $V_{th}$

1. Delete external circuit between the two terminals
2. Calculate the voltage between the two terminals
3. that's it

How to Calculate $R_{th}$

1. Remove external circuit
2. Set all independent sources to 0 (but not dependent ones)
3. Calculate the equivalent resistance between the terminals OR
4. If there's a source that's dependent on a value inside the circuit, then create a test source across the terminals (1V or 1A), then find the current or voltage across it (works for everything) OR
5. If there's both, find $V_{oc}$ and $I_{sc}$ (works for only independent too)

Norton Equivalent Circuits

• It's the same thing, but it's current instead of voltage, and the current source and resistor are in parallel
• And you find the equivalent current by shorting the two terminals