AndrewT said:
As Capain Mainwaring would say " Ohh, haven't got time for all that now "
It's dinner time !! Hungry!! Need feeding !!
Bon appetite again..
I am going to home now, for a lunch of course.. I will measure my OPAs DC offset (with inputs shorted) after the luch and will discuss the potential potentiometer events with that offset..
See.
I am going to home now, for a lunch of course.. I will measure my OPAs DC offset (with inputs shorted) after the luch and will discuss the potential potentiometer events with that offset..
See.
My OPA s output is 0.1mV... Without offset trim and while inputs shorted.
Does it cause any potentiometer harm in long term?
Does it cause any potentiometer harm in long term?
Hi,
No problem at all ? If you null it even that will reduce to zero, but be careful. It's not always straightforward measuring such things, and I would again use a low pass filter on the output to get a "truer" reading.
Does your meter actually read 0.000volts with the probes shorted ? If you swap the meter leads round does it show -0.1mv or something different 🙂
No problem at all ? If you null it even that will reduce to zero, but be careful. It's not always straightforward measuring such things, and I would again use a low pass filter on the output to get a "truer" reading.
Does your meter actually read 0.000volts with the probes shorted ? If you swap the meter leads round does it show -0.1mv or something different 🙂
Mad thoughts as you do, not just from todays posts but going way back.
Regarding power amps -- have the error signal fed to a sample/hold circuit that only operates at switch on for a minute or so and then say every 5 mins after that, just for long enough for a new error voltage to be aquired. Problems, well I suppose if there were significant drift of the offset then each time it corrects that could be audible.
Captain Mainwaring again " Your getting into the realms of fantasy now Mooly "
Next ? (Back to the preamp now) Use the output of the servo to correct the OPA via it's offset null terminals. That could interesting, perhaps setting a deliberate error up on one pin and correcting via the other, or perhaps some Opto scheme.
But I think with 0.1mv untrimmed we won't bother today.
It's Tea Time -- and not a moment too soon 🙂
Regarding power amps -- have the error signal fed to a sample/hold circuit that only operates at switch on for a minute or so and then say every 5 mins after that, just for long enough for a new error voltage to be aquired. Problems, well I suppose if there were significant drift of the offset then each time it corrects that could be audible.
Captain Mainwaring again " Your getting into the realms of fantasy now Mooly "
Next ? (Back to the preamp now) Use the output of the servo to correct the OPA via it's offset null terminals. That could interesting, perhaps setting a deliberate error up on one pin and correcting via the other, or perhaps some Opto scheme.
But I think with 0.1mv untrimmed we won't bother today.
It's Tea Time -- and not a moment too soon 🙂
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