How to calculate the energy and power of a signal?

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SUMMARY

This discussion focuses on the distinction between power signals and energy signals, specifically using the example of the signal ej(2t+π/4). Power is defined as the product of voltage and current (P=V*I), which can be calculated instantaneously or averaged over time. Energy is derived from the time integral of power. The signal ej(2t+π/4) is identified as a sine wave, which does not provide sufficient information regarding voltage, current, power, or energy calculations.

PREREQUISITES
  • Understanding of signal theory
  • Familiarity with complex exponentials in signal representation
  • Knowledge of electrical power calculations (P=V*I)
  • Basic calculus for integrating power to find energy
NEXT STEPS
  • Study the definitions and characteristics of power signals versus energy signals
  • Learn about the Fourier Transform and its application in signal analysis
  • Explore the concept of instantaneous power and average power calculations
  • Investigate the time-domain and frequency-domain representations of signals
USEFUL FOR

Students and professionals in electrical engineering, signal processing specialists, and anyone seeking to deepen their understanding of signal characteristics and power calculations.

Manoj Sahu
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I would like to improve my knowledge of signals. I just came across this topic while reading a book. So I would like to know how to find out that the given signal is power signal or energy signal. For example please solve the following and give your explanation in reference to that.
e^j(2t+π/4)
 
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I don't know what power signal or energy signal mean.

Power is voltage times current, P=V*I. You calculate that instantaneously. You can also calculate an average over any period you wish. Energy is the time integral of power. Those statements apply to all signals.

e^j(2t+π/4) is merely a sin wave. It tells you nothing about V or I or P or energy.
 
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Most likely this can only be answered by an "old timer". I am making measurements on an uA709 op amp (metal can). I would like to calculate the frequency rolloff curves (I can measure them). I assume the compensation is via the miller effect. To do the calculations I would need to know the gain of the transistors and the effective resistance seen at the compensation terminals, not including the values I put there. Anyone know those values?

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