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  1. Jimbo bob

    The input voltage of the ADC chip

    Hi again:), I know it has been a while, but I thought instead of making a new thread, I ask a relevant question here. To clarify, this is still related to the input of a specific ADC, but now there are a few more variable involved. I am planning to use an AD7730L analogue to digital converter...
  2. Jimbo bob

    Multiplexer digital input voltage limits

    Thank you Harald:). It makes sense and it seems that is the best way of going about solving this problem.
  3. Jimbo bob

    Multiplexer digital input voltage limits

    Hi everyone:), I was going through the data sheet for ADG706_707 multiplexer. I am planning to power it with +2.5V and -2.5V. When I go to the absolute ratings section on page 5 it says: and then there is a footnote for it: I was planning to feed the digital inputs of the multiplexer (i.e...
  4. Jimbo bob

    Strain gauge dilemma ( Or The Attack of The Gauges!!)

    Hi beedees :), I see that indeed your circuit and your description shows that we are both trying to achieve the same thing or a very similar thing. Just keep in mind that if your gauges are experiencing both tensions and compressions, you should expect both positive and negative output voltages...
  5. Jimbo bob

    Strain gauge dilemma ( Or The Attack of The Gauges!!)

    Wow:D. Thank you very much for your concise yet really informative explanation:). I have some understanding regarding instrumentation amplifiers and I was thinking of using a chip like INA126, but I changed my mind because I thought that the ADC chip and the circuit arrangement that I was using...
  6. Jimbo bob

    Strain gauge dilemma ( Or The Attack of The Gauges!!)

    Hi everyone :), I have 24 strain gauges installed on 24 individual rods (so one gauge per rod. SO MANY!!:eek:). I am thinking about coming up with a circuit which involves only one quarter bridge (do not enough gauges for half bridge and more) which allows all the 24 strain gauges to take turn...
  7. Jimbo bob

    Switching between Multiplexer channels without violating ADC sampling time

    Makes sense. Thanks!!:)
  8. Jimbo bob

    Switching between Multiplexer channels without violating ADC sampling time

    I see. I had a read of that section and it is quite interesting. Does that mean the sampling time is variable? I was looking everywhere for a constant value for the sampling time which I would expect to be a multiple of the ADC's clock cycle. Thank you very much for your help :D
  9. Jimbo bob

    Switching between Multiplexer channels without violating ADC sampling time

    Hi all :), I recently bought an AD7730LBR Bridge transducer chip so I can use it as an analogue to digital converter for my quarter bridge circuits. I am planning to use four 4051 Single 8-channel Analogue Multiplexers to read the output voltage of around twenty four quarter bridge circuits...
  10. Jimbo bob

    The input voltage of the ADC chip

    Cheers Harald :). So if I were to supply +5V from VDD to GND (i.e. GND = 0V and VDD = 5V), I can input 0V-0.1V....5V+0.1V (Buffer off) as the ADC's full scale, correct? When you mentioned "will not lead to reasonable results, did you say that because the full voltage scale of ADC was not used?
  11. Jimbo bob

    The input voltage of the ADC chip

    Hi everyone :), This is probably really trivial, but I could not find an explanation on it. I have attached a section of the PDF data sheet for an ADC chip (ADS1242). On page 2 of the data sheet there is a rectangular box with the title "ABSOLUTE MAXIMUM RATINGS". In that box, in front of "AIN...
  12. Jimbo bob

    Possible malfunction of a quarter bridge amplifier

    Thanks Harald. You are absolutely right about a circuit diagram making things quite easier. Unfortunately, I was not able to obtain such diagram for the time being. If the amplifier has run into clipping, then reducing the offset using the potentiometer on the circuit should possibly fix things...
  13. Jimbo bob

    Possible malfunction of a quarter bridge amplifier

    Hi dear enthusiasts :), One of my friends very kindly made me a strain gauge bridge amplifier around 6 months ago. I had a little play with it and put it aside. I have attached a picture of the amplifier circuit. The circuit was used to amplify the output voltage of a quarter bridge. My...
  14. Jimbo bob

    The resistance range of a potentiometer

    First of all I truly appreciate your input. What I am trying to achieve is to find potentiometers (need a pair of them) that I can setup with the accelerator pedal of a car that I would like to work on. The voltage outputs of the potentiometers will be transmitted to an engine control unit and...
  15. Jimbo bob

    The resistance range of a potentiometer

    Hi all :), I am looking to get a potentiometer. However, the manufacturer offers the device in a number of different resistance ranges i.e. 5K, 10K, 20K. I want to connect its output to the auxiliary input of a engine control unit and power it from 12V car battery. My question is should I be...
  16. Jimbo bob

    Clearing doubts on grounding electronics circuitry

    I believe that it is clear now for me thanks to you, BobK and Gryd3. :)
  17. Jimbo bob

    Clearing doubts on grounding electronics circuitry

    I believe that was the case. Because establishsing a wireless link using xbees and powering the Uno using ECU worked fine. It also worked fine when not only the USB was connected, but also Uno was powered by ECU. The power requirements of the USB were same as the USB port of a computer...
  18. Jimbo bob

    Clearing doubts on grounding electronics circuitry

    Hi Arouse1973 So the power and signal must have the same return path, right? Then is not what you are saying in answer to my second question contradicting your first answer? If the power and signal lines can be isolated then how can they have the same return path? Cheers :)
  19. Jimbo bob

    Clearing doubts on grounding electronics circuitry

    Hi everyone :) I have been having some doubts regarding the grounding of circuitry. At some point last year I had an Arduino Uno (a microcontroller board) on a vehicle. The Engine Control Unit (ECU) of the vehicle was sending some serial data to the Uno through a voltage level converter chip to...
  20. Jimbo bob

    The gauge factor of a strain gauge

    Quite useful. Thank you all!:)
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