[volt-nuts] Traveling Standards

Andreas Jahn Andreas_-_Jahn at t-online.de
Fri Aug 26 21:33:06 UTC 2011

>Any benefit in switching to a precision current source instead of the 

Hello Randy,

the only benefit of a current source that I see is that you can use
a lower supply voltage for the whole cirquit.
I use currently 9.35V for the LM399s.
So for me the use of a current source is mandatory.
But with 15V I would not do that.

With a current source instead of using one precision resistor
you will have to use at least two.
And you will have to find out how you can move the "hand adjustment" off
your cirquit with some decoupling capacitors without generating 

With the LM399 and a resistor its easy. At the heater I use 100nF directly
at the pins and 47uF not far away. At the output you will have to use 100nF 

The resistor will not be sensitive for RF or common mode voltages.
The voltage regulator should be decoupled too at input and output.

With best regards


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