A full-wave rectified 32vac voltage without filtering or smoothing components. Just a bridge rectifier connected across a transformer 32v secondary (no center taps) without a load connected to the output of the bridge.
What will my DMM read if it's in DCV mode when connected to this output?
Thanks, Dave
with no capacitors and a cheap average-reading DMM about 28V
"Jasen Betts" DaveC
** So more expensive DMMs read *OTHER* than average values on their DC volts ranges??Do tell.
.... Phil
-- Funny! ;) news:1ashi5p1cqgmsccirgseie1osejm8tau7q@4ax.com JF
If a good "True RMS" DMM is used, will the reading be different?
And can you help "teach me to fish" (show me the math)?
Thanks, Dave
2*sqrt(2)*32/3.14159265=28.8101221484
Integral from 0 to pi of Sin(theta)/pi = Average voltage of Sin(theta) = 2/pi therefore 1/sqrt(2) rms -> 2/pi therefore 1 -> 2*sqrt(2)/pi therefore 32 -> 2*sqrt(2)*32/pi
Howzit going, Phil?
A DC-coupled true RMS meter would read different from an averaging meter.
But in real life, diode leakage and capacitance and transformer inter-winding capacitance would probably result in an unpredictable reading.
John
"John Larkin"
** Dogs bark and cat go meow.But a DC voltmeter is always average responding.
** I have a 4.5 digit meter with true RMS AC ranges (200kHz BW) that can be DC coupled - a very handy feature.But one does not use it for the job the OP described without adding a load resistor, cos of the issues you mention.
.... Phil
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