DIYbanter - View Single Post - Logging mains voltage: Arduino or Raspberry Pi?

The Natural Philosopher[_2_]

On 14/04/18 17:28, wrote:
On Saturday, 14 April 2018 14:42:10 UTC+1, The Natural Philosopher wrote:

Most small mains transformers are run very close to core saturation, so
any large transients are likely to be clamped by the transformer.

Oh dear. A pseudo authoritative statement from someone who doesnt know
the difference between voltage and current.

So do you disagree with my claim that small transformers are usually
run close to core saturation at their rated voltage?

Yes

Do you disagree with my expectation that grossly overdriving such a
small transformer (with the transient to be measured) will cause its
output to saturate and give an incorrect measurement result?

Yes.

This
could be overcome by putting a resistor in series with the transformer
primary so that it is running at a small fraction of mains voltage.
Have a load resistor on the secondary may improve the performance as well.

Oh dear. Soemone who doesnt understand inductance either.

What exactly do you object to here? A resistively loaded transformer
looks like a resistor (apart from the leakage inductance) so in
conjunction with a series input resistor it will form a reasonable
potential divider thereby moving the operation well away from
saturation.

Please explain.

I am not here to teach you basic electronics when you think you know it
all already

John

--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly