[net.micro] Using squarewave AC with electronic gear

W8SDZ@SIMTEL20.ARPA (Keith Petersen) (03/17/85)

If you use a squarewave a.c. power source with most solid-state
electronic gear you won't get full output from your D.C. power supply.
This will result in a decrease in the ability of the regulators to
deal with power line voltage drops.

To prove this, measure the D.C. output (before the regulators) on your
electronic gear - first with regular A.C. power and then with
squarewave A.C.  You'll find that the D.C. output is LOWER with
squarewave A.C. feeding the power supply.  Reason: most solid-state
power supplies use capacitor-input filtering which means they depend
upon the "peak" A.C., not the average.  When you use squarewave A.C.
the peaks are just not there.  The typical 120v a.c. power line has a
peak voltage of around 140 volts.  Don't forget "120vac" is RMS, not
peak.

--Keith