Thevinin equivalent

Question

Answer 1

(1)

Step 1:

Find the Thevinins equivalent resistance.

1.Open the load resistor.

2.Open Current Sources and Short Voltage Sources.

3.Calculate the Open Circuit Resistance. The resultant open circuit resistance is the thevenin Resistance (R_TH).

Redraw the circuit :

The Resistance and are in series.

The resistance is in parallel to .

Equivalent resistance is .

Thevinins equivalent resistance is .

Solution :

Thevinins equivalent resistance is .

Answer 2

(2)

Step 1:

Find the thevinins equivalent voltage.

1.Open the load resistor.

2.Calculate the Open Circuit Voltage. This is the Thevenin Voltage (V_TH).

Use Superposition principle to calculate volatge across A and B.

Find the current through 10 resistor.

Super Position Theorem :

Take one voltage source at a time and replace all other with short or internal resistance.

Current in the circuit is .

Current in the circuit is .

Voltage drop acoss 10 resistor : .

.

Step 2:

Take one voltage source at a time and replace all other with short or internal resistance.

Current in the circuit is .

Current in the circuit is .

Voltage drop acoss 10 resistor : .

.

Step 3:

By superposition principle : 

The Voltage acoss the terminal A and B is .

Thevinins equivalent voltage is .

Solution :

Thevinins equivalent voltage is .