Thread: Superposition
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Old November 16th 07, 11:08 PM posted to rec.radio.amateur.antenna
Antonio Vernucci Antonio Vernucci is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 395
Default Superposition

Wave#1: V = 50v at 0 deg, I = 1.0a at 0 deg, P = 50 joules/sec

Wave#2: V = 50v at 45 deg, I = 1.0a at 45 deg, P = 50 joules/sec


50 joules/s are carried by Wave#1 if alone. The same applies to Wave#2

But if both waves are sumultaneouly present, the power carried by each wave when
alone is no longer a meaningful number. As a matter of fact when superposing two
coherent waves (same frequency, fixed phase relationship), one MUST first sum
voltages (or currents) and then calculate power.

Summing wave powers could only be done in case of incoherent waves.

In conclusion, the answer to your question is that the apparent extra 71
joules/s come front the fact that 100 joules/s taken as reference is a number
having no physical meaning.

73

Tony I0JX