Electrical Engineering - Energy Graph Question

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Discussion Overview

The discussion revolves around a homework problem in electrical engineering concerning the calculation of total energy absorbed by a device over a specified time period, based on current and voltage graphs. Participants explore methods for integrating power over time using given equations and functions.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant requests help with a homework problem involving the calculation of energy from current and voltage graphs.
  • Another participant suggests using discrete intervals to calculate power by multiplying current and voltage values, followed by integrating the power function to find energy.
  • A different participant expresses difficulty with the voltage graph, noting that it complicates their approach to finding a function for the voltage to multiply with the current.
  • One participant identifies that the voltage is constant between specific time intervals, suggesting a simple function for that period.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the best approach to solve the problem, as there are differing opinions on how to handle the voltage function and its impact on the calculation.

Contextual Notes

There are unresolved aspects regarding the integration process and the specific functions to be used for both current and voltage, particularly at the transition points in the graphs.

Larrytsai
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Homework Statement


Question number 3!, I attached it. Need help!

Figure 1 shows the current through and the voltage across a device. Find the total energy absorbed by the device fore the period 0<t<4.


Homework Equations


integral of p = energy
P=VI


The Attempt at a Solution


Just need the algorithm to solving these kinds of problems, I am kind of thrown off at the instantaneous change.
 

Attachments

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One way you could think about this problem is by taking discrete intervals on the current graph and voltage graph and multiplying these values together. This will result in a graph that describes the power dissipation in the device over the given time interval. Then it will just be a matter of finding the area under the curve (integrating the resulting power function).
 
Yeah I thought about that approach but when I look at the voltage it comepletely throws me off. I am able to break the current into 2 separate intervals with the function y1=25x and 0<t<2, y2=-25x 2<t<4, but for the voltage at t=2 its constant and I can't come up with a function to multply with my current.
 
For the voltage between t=1 and t=3, the function describing the voltage is just a constant, or y=10.
 

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