[volt-nuts] Tilt effect on Keithley 2000
Andreas_-_Jahn at t-online.de
Mon Sep 6 05:00:23 UTC 2010
> Joe Geller suggests the current draw of the LM399 heater is sensitive
> to very small changes in ambient temperature, he exploits this in his
> microgust anemometer circuit. When orienting an exposed chip, very
> small temperature gradients exists between open air and a table,
> particularly with fan or window making small air currents.
thanks for your contribution.
In my LM399 references I wanted to have a minimum power
consupmtion when using battery supply.
So I did not remove the foam cup of the device.
Instead I packaged the small PCB with the LM399 and the
temperature compensated current source into a housing of
polystyrene foam. This housing is packaged into a card box.
So there should not be much air current inside.
The most confusing fact is that the power consumption
is a minimum when turning the LM399s up side down
with the pins in upper direction. The foam cup has a
relative large hole for all 4 pins.
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