Skip to main content
Electrical Engineering

Return to Question

added 21 characters in body; edited title
Source Link
ocrdu
ocrdu
  • 9.3k
  • 23
  • 32
  • 42

Can Powerpower absorbed be negative and Power Suppliedpower supplied be Positivepositive?

I've been working on these end chapter problems from my book and noticed that something is either wrong and contradicting to the concept I was taught, or there is some concept I missed entirely.

For the 2 problems below hereHere are the figures, for the two problems below:

enter image description here

Notice that for problem 1.21 that it says that element A is "Absorbing""absorbing" power and problem 1.22 that it is "Supplying""supplying" power.

When iI do the calculations based on the following rule, Current leaving the "+" side and Powerpower > 0, then Powerpower is "Supplied""supplied" otherwise if Powerpower < 0 then Powerpower is "Absorbed""absorbed"

So 3A3 A leaves 15V15 V from the + end and the Powerpower, P = VI, is 45W45 W, 45 > 0 and thus power should be "Supplied""supplied" but the problem says it is being Absorbed?Amabsorbed.

Again with problem 1.22 but this time, it is entering + so the rule states, Current current entering the "+" end and Powerpower > 0, then Powerpower is "Absorbed""absorbed" otherwise if Powerpower < 0 then Powerpower is "Supplied""supplied"

So 2A2 A enters 20V20 V from the + end and the Powerpower is 40W40 W, 40 > 0 thus power should be "Absorbed" but"absorbed", but the problem says it is being Suppliedsupplied.

Now back to main question, is it that I am wrong, and through some concept I missed, that problem 1.21 is actually -45V45 V absorbed and not -45 V supplied, and the same with problem 1.22?

Can Power absorbed be negative and Power Supplied be Positive?

I've been working on these end chapter problems from my book and noticed that something is either wrong and contradicting to the concept I was taught or some concept I missed entirely.

For the 2 problems below here are the figures,

enter image description here

Notice that for problem 1.21 that it says that element A is "Absorbing" power and problem 1.22 that it is "Supplying" power.

When i do the calculations based on the following rule, Current leaving the "+" side and Power > 0, then Power is "Supplied" otherwise if Power < 0 then Power is "Absorbed"

So 3A leaves 15V from the + end and the Power, P = VI, is 45W, 45 > 0 and thus power should be "Supplied" but the problem says it is being Absorbed?

Again with problem 1.22 but this time, it is entering + so the rule states, Current entering the "+" end and Power > 0, then Power is "Absorbed" otherwise if Power < 0 then Power is "Supplied"

So 2A enters 20V from the + end and the Power is 40W, 40 > 0 thus power should be "Absorbed" but the problem says it is being Supplied.

Now back to main question, is it that I am wrong, and through some concept I missed, that problem 1.21 is actually -45V absorbed and not -45 supplied and same with problem 1.22?

Can power absorbed be negative and power supplied be positive?

I've been working on these end chapter problems from my book and noticed that something is either wrong and contradicting to the concept I was taught, or there is some concept I missed entirely.

Here are the figures for the two problems below:

enter image description here

Notice that for problem 1.21 it says that element A is "absorbing" power and problem 1.22 that it is "supplying" power.

When I do the calculations based on the following rule, Current leaving the "+" side and power > 0, then power is "supplied" otherwise if power < 0 then power is "absorbed"

So 3 A leaves 15 V from the + end and the power, P = VI, is 45 W, 45 > 0 and thus power should be "supplied" but the problem says it is being Amabsorbed.

Again with problem 1.22 but this time, it is entering + so the rule states, current entering the "+" end and power > 0, then power is "absorbed" otherwise if power < 0 then power is "supplied"

So 2 A enters 20 V from the + end and the power is 40 W, 40 > 0 thus power should be "absorbed", but the problem says it is being supplied.

Now back to main question, is it that I am wrong, and through some concept I missed, that problem 1.21 is actually -45 V absorbed and not -45 V supplied, and the same with problem 1.22?

Source Link
DoubleA
DoubleA
  • 41
  • 6

Can Power absorbed be negative and Power Supplied be Positive?

I've been working on these end chapter problems from my book and noticed that something is either wrong and contradicting to the concept I was taught or some concept I missed entirely.

For the 2 problems below here are the figures,

enter image description here

Notice that for problem 1.21 that it says that element A is "Absorbing" power and problem 1.22 that it is "Supplying" power.

When i do the calculations based on the following rule, Current leaving the "+" side and Power > 0, then Power is "Supplied" otherwise if Power < 0 then Power is "Absorbed"

So 3A leaves 15V from the + end and the Power, P = VI, is 45W, 45 > 0 and thus power should be "Supplied" but the problem says it is being Absorbed?

Again with problem 1.22 but this time, it is entering + so the rule states, Current entering the "+" end and Power > 0, then Power is "Absorbed" otherwise if Power < 0 then Power is "Supplied"

So 2A enters 20V from the + end and the Power is 40W, 40 > 0 thus power should be "Absorbed" but the problem says it is being Supplied.

Now back to main question, is it that I am wrong, and through some concept I missed, that problem 1.21 is actually -45V absorbed and not -45 supplied and same with problem 1.22?