The Natural Philosopher wrote:

On 08/06/2019 10:39, Roger Hayter wrote:
The Natural Philosopher wrote:

On 08/06/2019 09:47, Harry Bloomfield wrote:
expressed precisely :
On Thursday, 6 June 2019 15:12:49 UTC+1, Harry Bloomfield wrote:
on 05/06/2019, tabbypurr supposed :

All Brian's points are incorrect except that they do often get stiff
due to limescale or corrosion.
A diode will give 240v x 0.707 rms volts, which is more than 120.

No, it will be 50% of the AC waveform, less a bit for the fraction of
a volt lost across the junction.

do you ever get anything right?

Yes, quite often actually and I am right this time too.

Dont see tabbypurr as he is plonked, but yes, he is talking cock and for
a resistive load, a diode will indeed halve the power.

Its the same watts for half the time so to speak.

'RMS volts' on a clipped waveform is almost not worth even thinking
about. Its a seriously damaged concept by then.

Unlike RMS power, which is a seriously confused concept, RMS voltage of
any repetitive waveform, regardless of shape, remains a precisely
defined quantity and, importantly, continues to goven the average power
delivered to a resistive load over that repetitive waveform. The
relationship to peak voltage is, of course, arbitrary in the general
case. But a rectified sine wave still allows simple, accurate
calculation. But not by me, at least at this time in the morning.



Easiest is to simply halve the power of a full wave as it only is there
half the time and take the root.

Agreed!

--

Roger Hayter