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On Jul 8, 11:16*pm, "Alex Pogossov" wrote:
"Phil Allison" wrote in message

...







"Alex Pogossov"

In any case, an abrupt interruption of the plate current will cause a
voltage spike on the OPT primary. The stored magnetisation energy of
Lp*(Ia^2)/2 will have to be dissipated. Lp can be quite high in a decent
amp. If a load is connected, then the energy will be dissipated in the
load giving you a loud crack in the speaker. A residual smaller energy
stored in the leakage inductance Ls*(Ia^2)/2 will most likely be safely
dissipated in a snubber of say 2200pF+5K usually connected in parallel to
the OPT primary.

But what is the load is not connected? Then the huge magnetisation energy

** Why huge ???

If Lp is say 100H and *Ia = 0.1A *then how many Joules is that ?

Apparently 0.5J.

It is the same as charging a 10uF to 315V or 47uF to 160V. If you are in
Europe or Australia, try charging 10uF from the grid through a diode and
then discharging it with a screwdriver... The closer you keep the cap to
your face when discharging -- the better... Then you will see if it is huge
or not... It is all subjective after all... If you are in the US, use 47uF
for a similar experiment.

Enjoy

Alex- Hide quoted text -

- Show quoted text -

We used to use 100 uF@ 500VDC in my highschool to play jokes in the
electronics shop. Gives a very nice wake-up jolt , especially to those
with sweaty palms . . .