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???
05/02/05 20:50
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#92759 - Track the drift
Responding to: ???'s previous message
Prahlad J. Purohit said:

What are these components that track each others drift. I couldnt get exactly what you mean. Please elaborate a bit more on this.
Prahlad Purohit


Think, as an example, of resistors in a Wheatstone bridge. You'll like all of them have *the same* temperature coefficient and be at the same temperature all the time so the changes in temp get cancelled in the final result. Analyze the bridge with Rx(1+DeltaTempx) with a different DeltaTempx for each resistor (x=1..4) so you can get a general equation, and then make all DeltaTempx equal. You'll get the DeltaTemp cancelled which means the circuit behavior doesn't depend on temperature.

Another example: in circuits with transistors, the base-emitter junction always has a TempCo of (approx.) -0.6mV/degree. This property can be useful to measure temp, but in another applications could led to big drifts. So you can employ another transistor as P-N diode, best if gotten from the same batch, and change the resistor polarizing network to countermeasure the tempco of your main transistor.

I don't know it I made it clear...

Regards.
Enrique.




List of 16 messages in thread
TopicAuthorDate
WEOT: Signal Conditioning the right way.            01/01/70 00:00      
   Calibration            01/01/70 00:00      
      Re: Caliberation.            01/01/70 00:00      
         Assumptions wrong.            01/01/70 00:00      
            Re: Wrong Assumption.            01/01/70 00:00      
            Tracking the offset.            01/01/70 00:00      
               re:drift            01/01/70 00:00      
                  Drift compentsation            01/01/70 00:00      
               Track the drift            01/01/70 00:00      
                  another track            01/01/70 00:00      
   Signal conditioniong            01/01/70 00:00      
   Choosing precision parts is the remedy            01/01/70 00:00      
      Re: Choosing precision parts.            01/01/70 00:00      
         Ratio is important            01/01/70 00:00      
   wikipedia for op-amp            01/01/70 00:00      
   power supply noise            01/01/70 00:00      

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