[volt-nuts] physical explanation of the tilt effect?

Andreas Jahn Andreas_-_Jahn at t-online.de
Sun Sep 19 15:54:42 UTC 2010

> A thermal effect could be induced by different heat convection flow from 
> the warm LTZ to the surrounding solder joints.
> I isolated the LTZ1000 additionally by a PS cap around it, so i really 
> wonder...
> Anyhow, if anybody finds "the missing link" between the drift effect and 
> the physical property, it would be interesting to
> improve the assembly.


on my LM399 where heater, sensor and regulator are on the same chip I 
measured a different heater current depending on orientation. So I think 
since heater, reference element and temperature sensing element are not 
exactly at the same location and the temperature spreading between the 3 
elements is not exact symmetrical there will be small temperature 
differences depending on wether the heater is exactly below the temperature 
sensor or exactly below the reference element.

By the way: on LM399 the heater current is a minimum when the device is 
mounted upside down (with the pins in the upside direction).

with best regards


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