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???
03/04/05 01:36
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 		 #89058 - Re: Digital Pots.
Responding to: ???'s previous message
Dear Ijaz,
Thanks for your prompt reply,


A suitable digital potentiometer might serve your purpose. What level of precision is required for the feedback resistor? The problem with digital pots is that they have a certain minimum resistance per step.


I need 0.1% maximum tolerance with the said 3 resistors and I need following 3 values.
1. 44k
2. 22k
3. 14.67k

I will try searching a digital pot that can match my requirements but as you said they have fixed taps let me see if I can get the above 3 values with them.


If a very very high precision is required, I would use fixed resistors with some sort of software controlled switching.


Yes a high precision is required can you please give some more information on software controlled switching is it switching relays / Analog switches or something else.

Thanks for your reply.

Regards,
Prahlad Purohit


List of 37 messages in thread
TopicAuthorDate
Three Gains?            01/01/70 00:00      
   Digital Pots            01/01/70 00:00      
      Re: Digital Pots.            01/01/70 00:00      
         precision digital pots can not be found            01/01/70 00:00      
   PGA are cheap too            01/01/70 00:00      
      Easiest Method            01/01/70 00:00      
         Re: Easiest method.            01/01/70 00:00      
            Need not to be a problem            01/01/70 00:00      
            Three gains            01/01/70 00:00      
               precision            01/01/70 00:00      
                  ratio is precision            01/01/70 00:00      
      Re: PGA            01/01/70 00:00      
   could you            01/01/70 00:00      
      Re: Logarithmic Amplifier.            01/01/70 00:00      
         never used one            01/01/70 00:00      
   Use three independent lines            01/01/70 00:00      
      Re: Three Independent Lines.            01/01/70 00:00      
         Not three integrators, but...            01/01/70 00:00      
            Re: Three Amp sections for three gains            01/01/70 00:00      
               Is it unity gain buffer or I to V conv.            01/01/70 00:00      
                  it's part of your rectifier            01/01/70 00:00      
                     Thanks for clarification.            01/01/70 00:00      
               Maybe some protection scheme for ADC            01/01/70 00:00      
                  Re: Some protection for ADC.            01/01/70 00:00      
   Higher resolution avoids gain switcing            01/01/70 00:00      
      Re: Higher Resolution.            01/01/70 00:00      
   You can use better profesional method.            01/01/70 00:00      
      low voltage analog switching            01/01/70 00:00      
         Re: Low voltage analog switch.            01/01/70 00:00      
            voltage            01/01/70 00:00      
            Seebeck-effect, thermo elements            01/01/70 00:00      
               better - yes            01/01/70 00:00      
               English english            01/01/70 00:00      
                  Re: English            01/01/70 00:00      
                  Thanks!            01/01/70 00:00      
      Re: Profesional method.            01/01/70 00:00      
         Mechanical relays.            01/01/70 00:00      

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