For procedures, see your electrical laboratory manual.

Title: Maximum Power Transfer


Aim

1. To connect and test simple DC and AC circuits.
2. To operate the avometer on DC and AC voltage and current ranges.
3. To verify the maximum power transfer theorem for DC and AC circuits.

Apparatus

— DC experiment
1. 6V DC power supply
2. Two 500 Rheostats
3. Two Avometers

— AC experiment
1. One 2A Variac
2. Two 500 Rheostats
3. Two Avometers
4. One Harris AC voltmeter 0.300V
5. One Inductor
6. One Variable capacitor

Theory

The maximum power transfer theorem states that maximum power is transferred from the circuit to the load when the resistance/impedance is made equal or matched to the internal resistance/impedance of the source or circuit that is providing power to the load.
In other words" A resistive load will be consumptive maximum power from the supply when the load resistor is equal to the equivalent (Thevenin) network resister".

The maximum power transfer theorem determines the value of resistance RL for which, the maximum power will be transferred from source to it. Actually, the maximum power, drawn from the source, depends upon the value of the load resistance.

The maximum power transfer does not coincide with maximum efficiency.

Application of The Maximum Power Transfer theorem to AC power distribution will not result in maximum or even high efficiency. The goal of high efficiency is more important for AC power distribution, which dictates a relatively low generator impedance compared to the load impedance.

Similar to AC power distribution, high fidelity audio amplifiers are designed for a relatively low output impedance and a relatively high speaker load impedance. As a ratio, "output impedance": "load impedance" is known as damping factor, typically in the range of 100 to 1000. [rar] [dfd]

Maximum power transfer does not coincide with the goal of the lowest noise. For example, the low-level radio frequency amplifier between the antenna and a radio receiver is often designed for the lowest possible noise. This often requires a mismatch of the amplifier input impedance to the antenna as compared with that dictated by the maximum power transfer theorem.