Maximum Power Transfer Theorem Lab Report

THE HONG KONG POLYTECHNIC UNIVERSITY EE2002A – E01
Department of Electrical Engineering

Date: 21/09/2015, Venue: EF402
1. Kirchhoff's Laws,
2. Equivalent resistance (Y–Δ Transformation), and
3. Maximum Power Transfer Theorem
Group: 7
Name:
Chan Shui Fung (15067344d)
Lo Kin Hei (15072591d)
Ng Wai Fung (15071465d) (Author)

Introduction:
The objectives of this experiment are to
Verify Kirchhoff's laws,
Determine the equivalent resistance of a network, and
Study the maximum power transfer theorem.

Equipment in this experiment:
D.C power supply
Multi-meter
Experimental Board

Experimental methods (Kirchhoff's Law and Equivalent resistance):
For both experiments: Set the current limit of the power supply to 0.5 A. Then connect it to

If we consider the calculation mistake and experimental error, the results of (2) and (5) are very close to 0. The results is verify the Kirchhoff's Current laws.

Kirchhoff's Voltage Law:
Adjust the D.C Supply to keep the voltage across Node A and C to 5V.
Measure the voltage around loop AMBCA.
Loop AMBCA
Voltage (V)
VAM
1.30
VMB
0.3
VBC
3.45
VCA
-5.06
Calculate VAM + VMB + VBC + VCA.
Answer:
VAM + VMB + VBC + VCA
= 1.3 + 0.3 + 3.45 - 5.06
= -0.01 V
Measure the voltage around loop ABMCA.
Loop ABMCA
Voltage (V)
VAB
1.607
VBM
-0.3
VMC
3.75
VCA
-5.06
Calculate VAB + VBM + VMC + VCA.
Answer:
VAB + VBM + VMC + VCA
= 1.607 - 0.3 + 3.75 - 5.06
= -0.003 V
Comment on the result of (3) and (5).
If we consider the calculation mistake and experimental error, the results of (2) and (5) are very close to 0. The results is verify the Kirchhoff's Voltage laws.

Equivalent resistance (Star – to – Delta Transform / Delta – to – Star Transform):
Turn off the power of the supply and use multi-meter to measure the equivalent resistance RAC of the network shown as Page 1 between A and C. Do not remove the power supply from the

Plot the power delivered to the load against RL.

From the power curve obtained, find the maximum power dissipated and the corresponding value of RL.
Answer: From the power curve, we found that the maximum power dissipated is 0.6401mW and the corresponding value of RL is 10000 Ω.
Determine the total resistance of the supply section using the condition for maximum power transfer.
Answer: The total resistance of supply section using the condition for max. Power supply (when Ri = RL, then the corresponding power value will be max.), then the total resistance is equal to 20k Ω.
Repeat the above procedures with Ri = 15k Ω and Ri = 22k Ω, so as to obtain families of power curve.

For Ri = 15k Ω (with RL varying from 10k Ω to 25k Ω)
VL (V)
2.01
2.24
2.44
2.53
2.61
2.75
2.89
3.01
3.08
IL (mA)
0.201
0.1867
0.1743
0.168
0.1631
0.1528
0.1445
0.1368
0.1311
RL (Ω)
10000
12000
14000
15000
16000
18000
20000
22000
23500
PL (mW)
0.4040
0.4181
0.4253
0.4267
0.4258
0.4201
0.4167