If you do modify the circuit, you will probably want to decrease the
series R. Even though the external loads are likely to be in the
megohm range, the feedback load is significant, and likely the
biggest part, except for fault conditions. For lowest noise and
suppression of effects due to bias
On 11/27/2012 07:37 PM, ed breya wrote:
> I'm not sure how much elaboration is needed, but here's some:
>
> If you take all of the feedback from the output terminal, that's better for DC
> accuracy by eliminating the voltage drop of the series resistor, while still
> providing some overload protec
I'm not sure how much elaboration is needed, but here's some:
If you take all of the feedback from the output terminal, that's
better for DC accuracy by eliminating the voltage drop of the series
resistor, while still providing some overload protection to the
opamp. But, it also decreases phas
Hi Ed,
I am a little confused with regard to your paragraphs 3 & 4. Could you
elaborate
on those two paragraphs ?
thank you,
BillWB6BNQ
ed breya wrote:
> The simplest way to drop the output impedance without adding much
> circuitry is to just change the series R to 100 ohms or so - that
The simplest way to drop the output impedance without adding much
circuitry is to just change the series R to 100 ohms or so - that
would still give pretty good isolation from capacitive loading.
If the R is dropped to zero, the DC performance will be best, but
you'll have to worry about the a
Hi Bob,
If all you intend to use the 10 volt output, perhaps it would be better to move
the
sense string positive terminal to the output banana jack leaving the 1K
resistor in the
circuit. That is, take the top connection R8A and move it to the other side of
R18,
preferably right at the banana
You can add an voltage follower. Made one using a LT1052 and LT1010 ( if i have
the number right, a power opamp) the design is from Williams, he uses it in is
his sub 1ppm reference.
I use it to buffer the 731A, that is less stable as my home made LM399, that is
getting more stable every week.
The 731A is specified to have an output impedance of less than 1.1K in the 10V
setting. A meter with 10 M input Z therefore causes a .01% (100 ppm) reading
error.
I understand that when operated using a null meter the output impedance is not a
problem. I would like to use my 731A as a bench sta
