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Old 08-22-2014, 10:20 PM   #10
Mr. Ham
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Join Date: Aug 2014
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Quote:
Originally Posted by NN5I View Post
RMS for a sinusoid is 0.707 times the peak-to-peak, which in this case is .707 times 2v, not 1v, so the RMS for this sinusoid is about 1.414 volts, and I was off by a factor of two. Oops, I used the peak value instead of the peak-to-peak.

This square wave, which is not a sinusoid, is always either 12.5v positive or 12.5v negative; so it has the same heating effect on a resistor as 12.5v dc. Its RMS value is 12.5v because it's a square wave and not a sinusoid.

Back when I made my living as a circuit design engineer, I must have designed hundreds of circuits using 741 op-amps and their predecessor the Fairchild 709 -- both created by my personal hero of the time, Robert J Widlar, and his sidekick James N Giles. Your Wiki link brought back memories. Widlar left Fairchild for National Semiconductor, demanded a piece of the action, and got stinkin' rich when NSC took the market away from Fairchild.
I think at one time this was a question you had to know to pass your Technician Class License exam, later it was moved to the General Class exam. Today, the exams are so dumbed down, about all you have to do is speel your name right on the application to get your Technician Class License.
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