Thevenin's Theorem

Thevenin's theorem is a procedure by which we change a complex network in to simple network called thevenin's equivalent circuit.

Thevenin’s equivalent circuit of an open circuit voltage, thevenin voltage, Vth and the total resistance from the open terminals side, thevenin's equivalent resistance, Rth. Connected both thevenin's quantities in series. In this way we can find the current or voltage of any branch of the circuit.

Thevenin's Theorem Circuit Diagram
Thevenin's Theorem Circuit Diagram

STEP#1

Remove that resistance in which current is wanted

Thevenin's Theorem Circuit Step 1
Thevenin's Theorem Circuit Step 1

STEP#2

Find the open circuit voltage, VAB called thevenin's equivalent voltage, Vth.

Thevenin's Theorem Formula Step 2

 

STEP#3

Find the total resistance, from open terminals A and B side is called thevenin's equivalent resistance, Rth removing actual voltage source from the circuit.

Thevenin's Theorem Circuit Step 3
Thevenin's Theorem Circuit Step 3
Thevenin's Theorem Formula Step 3

STEP # 4

Connect Vth and Rth in series. This will be the thevenin's equivalent circuit.

Thevenin's Theorem Circuit Step 4
Thevenin's Theorem Circuit Step 4

STEP#5

Reconnect the RL between the open terminals of the thevenin's equivalent circuit.

Thevenin's Theorem Circuit Step 5
Thevenin's Theorem Circuit Step 5

STEP#6

Find the current in RL

Thevenin's Theorem Formula Step 6

As both resistances are connected in series so the in RL. and Rth are same.

Category
Basic Electronics