Determine the average power absorbed and supplied by each element in the network in Figure P5.13

Determine the average power absorbed and supplied by each...

Key Concepts

Average Power

Average power in electrical circuits is defined as the mean value of the instantaneous power over a complete cycle or specified period. It represents the net energy conversion rate and is calculated as the product of voltage and current, taking into account any phase difference in AC circuits or constant values in DC circuits. This concept is fundamental when analyzing energy distribution across network elements.

Power Absorption and Power Supply

This concept distinguishes between elements that absorb power, such as resistors and loads, and those that supply power, like voltage sources. The calculation involves using the passive sign convention where power absorbed by a circuit element is considered positive if the current enters through its positive terminal, and negative if the element is delivering or supplying power to the circuit.

Passive Sign Convention

The passive sign convention is used to analyze power within a circuit by assuming that current entering the positive terminal of an element indicates power absorption. This helps in clearly defining whether a component is consuming or delivering energy, which is critical for accounting for energy flows in any network analysis.

Circuit Analysis Techniques

Techniques such as Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL) are essential for analyzing circuits. They allow for the formulation of equations that describe voltage drops and current flows within a network, ultimately enabling the accurate calculation of currents and voltages needed to determine the power absorbed or delivered by each element in the circuit.

Transcript

00:01 All right.

00:02 I'm going to work a problem where we have a parallel circuit and we are determining the power in each of the elements.

00:10 The fact that it's a parallel circuit doesn't really play much into it.

00:14 It is still primarily a matter of power is equal to voltage times current and passive sign convention.

00:24 That if it is being absorbed, then it is positive sign.

00:29 And if it is being supplied, then it is a negative sign.

00:34 And so we can work our way around the elements in the circuit.

00:39 It's lovely that the current is provided.

00:42 It is drawn.

00:43 We know the direction.

00:45 And we know the magnitude.

00:46 And there's one dependent source in there, but it should be pretty straightforward also.

00:51 So if we look at the first, at the power supply, its power is equal to current times voltage.

01:01 And that is a current of four amps at that part of the circuit times the voltage of 36 volts.

01:10 And so that is 144 watts.

01:14 And power, the current, rather, is flowing out of the positive terminal, means it's supplying.

01:20 So that is a negative 144.

01:24 Then, moving on to the next one, in element 1, i still have a current of 4.

01:34 Amps and i have a voltage of 12 volts and here it is flowing into the positive and so i have 48 watts and is being absorbed so they could see positive sign then i can go ahead and do element 2 at that branch then the current is 2 amps and its voltage is 24 volts so that is also 48 watts...

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