On Saturday, 8 June 2019 10:34:29 UTC+1, Steve Walker wrote:
On 08/06/2019 09:45, Harry Bloomfield wrote:
Steve Walker expressed precisely :

Of a sinewave, not a half-wave rectified sine wave.

Sinewave: 339V / sqrt(2) = 240V RMS

Half-wave rectified sinewave: 339V / 2 = 169.5V RMS

SteveW

169.5v x 0.707= 119.83v RMS..

Peak voltage is 339V for both full and half-wave rectified sinewaves.
The equations for RMS voltage differ in each case. A quick google will
show you them and they are as I quoted above. You have taken the RMS
(not peak) voltage of a half-wave rectified sinewave and multiplied it
by the factor for converting a full-wave sinewave's peak voltage into an
RMS one!

SteveW

I don't think Harry has a clue what he's done.