Are you sure? Perry was proposing to use a TL431 to
make an oven, using its famous temperature sensitivity,
and inside the oven would be another TL431 that acted
as a voltage reference.
Every oven I have ever seen that is temperature controlled
has a part that is quite good at measuring temperature at
the helm.
-Chuck Harris
Poul-Henning Kamp wrote:
--------
In message <[email protected]>, Pe
rry Sandeen writes:
OK, but why? The temperature would be stable so the resistorsand
reference diode wouldn't drift.
No, the temperature is not stable, not even close.
Given that the TL431 is quite good at measuring temperature, that
makes it unsuitable in this case.
I have identified one source of the temperature fluctuations: The
series pass transistor of the +20V rail is located right beneath
the A15 PCB, so any variation in mains (or EXT DC) voltage causes
the A15 temperature to change accordingly.
More details here:
http://phk.freebsd.dk/hacks/HP5065A/20150903_psu/
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