CT2

Question 1

how is internal resistance often shown in the circuit

Answer 1

Question 2

Equation for V_L , taking into account internal resistance?

Answer 2

V_L = V_S - I_LR_S

Question 3

Equation for I_L , taking into account internal resistance?

Answer 3

I_L = I_S - (V_L/R_S)

Question 4

Define Thévenin’s theorem?

Answer 4

Thévenin’s theorem says that the effect of a complicated linear circuit on a particular circuit element can be analysed by replacing the circuit, other than the element under analysis, by an equivalent circuit comprising a voltage source with internal resistance,

Question 5

Thévenin equivalent circuit?

Answer 5

Question 6

The procedure to find V_TH and R_TH, Step 1?

Answer 6

Remove the circuit element that you wish to find the current in, or voltage across,

Question 7

The procedure to find V_TH and R_TH, Step 1?

Answer 7

1. Calculate the voltage produced by the remaining circuit across the open-circuited terminals of the removed element. The calculated voltage corresponds to VTH.
2. There is no voltage drop across R2 since its current is zero; therefore this can be done using the potential divider equation.

Question 8

Equation for V_TH?

Answer 8

Question 9

The procedure to find V_TH and R_TH, Step 2?

Answer 9

• Next zero the voltage and current sources and calculate the resistance RTH looking back into the open-circuited terminals.
  
  • Zeroed voltage sources approximate to short circuits, I.e. wire link with R=0. Practical voltage sources have an internal resistance, Rs, and this is rather than R=0 should be used if its value is known.
  • Zeroed current sources approximate to open circuits, cut wire R = infinity. Practical current sources have an internal resistance, Rs, and this rather than R=0 should be used if its value is known.

Question 10

The procedure to find V_TH and R_TH, Step 4?

Answer 10

The Thévenin equivalent circuit is then added to the removed element to calculate its operating conditions.

Question 11

Why do we need the Maximum power transfer theorem?

Answer 11

It is important in some circumstances to know the maximum power that can be delivered to a load by practical sources and circuits.

Question 12

Equation for Maximum power transfer theorem?

Answer 12

Question 13

What are the normal conditions for maximum power trasnfer within a circuit?

Answer 13

The maximum power transfer takes place when the load resistance is equal to the source internal resistance. Setting RL to maximise PL is known as matching the load.