Hi,
I got the following brainteaser I can't handle with: what power we'll get on a resistor powered from 100W amplifier set on the level -40dB, when the source is a CD-player producing white noise at level -36 dB ? What current flows thru that resistor ? We assume, that all the circuits are linear.
TIA jvereker
If I remember correctly...
0dB would be 100W and you have -76dBso the output is
= 100 x antilog (-76/10) = 2.5uW
which sounds a bit low.
0 dB is meaningless as stated here. 0 dBm would mean 1 mW is the reference level.
reference
So the solution is...???
Why? The 0 dB on the meter would correspond to the full output of the amplifier...this sounds like an exam/homework question anyway.
How can we calculate the current without the resistor value anyway?
Tom
What is the resistor value?
If this is homework, it is more like stupid busywork.
I suppose one could assume 0 Db = full output, but that would need to be stated up front. The dB system is often abused and misused. Without a reference level, (i.e. dBmV, dBU, dBA, dBSPL, dBW, dBm, dBV, dBf, dBu, dBk, dBd, ad nauseum) the dB is often meaningless since it is not an SI unit.
The way I read it the OP added that bit about current. The question says "power".
And, as is the norm, forum members dance around each other and the OP never reappears. Sigh!
I'm having more and more difficulty these days with providing any measured, and thought-out response to these queries. I'm starting to understand the frequent nasty responses found on UseNet.
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