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  1. R

    precision voltage regulator adjustable

    Thanks
  2. R

    precision voltage regulator adjustable

    Thanks for your help. So when you say potential divider I presume you mean a RC low pass filter?
  3. R

    precision voltage regulator adjustable

    The acceptable resolution is 0.25mV. with a tolerance of 5 percent. This is used to simulate a change of 5mV within a certain time to detect heat. The rare of change can then alert if heat has risen quickly indicating a fire.
  4. R

    precision voltage regulator adjustable

    Hi all, I am looking to build a precision adjustable voltage regulator. I need to be able to control a voltage in the range of 5 to 10mV with great accuracy using a microcontroller. The other issue is that from the microcontroller I have a length of 2 core screened wire (around 500mm in length)...
  5. R

    Floating Dc Current Source

    Hi Ted, I will draw a schematic. I will post it asap. Thanks
  6. R

    Floating Dc Current Source

    It is this current output that I am trying to float.
  7. R

    Floating Dc Current Source

    Thanks for the replies. I have a DAC outputting voltage, this is fed into an opamp. The opamp has negative feedback that includes a FET and sense resistor that is fed into the other end of the opamp input. So for example the voltage from the DAC divided by the sense resistor gives me the...
  8. R

    Floating Dc Current Source

    The power is going to be either a DAC or LDO voltage regulator.
  9. R

    Floating Dc Current Source

    No it's not for medical equipment.
  10. R

    Floating Dc Current Source

    Hi all, I was wondering if someone coulf help me, I am looking to build a floating current source (dc). this will be used to supply a current of between 1uA to 300uA. I was thinking of the best way to go about this,, perhaps an isolation amplifier or opto device. Any ideas? The current will...
  11. R

    Help With Circuit

    Thanks.
  12. R

    Help With Circuit

    Hi Steve, Many thanks for your help. We are talking microamperes, typically from 1-100uA. But it needs to be a negative current. You have helped me immensely, I am really thankful. Best regards, Raj
  13. R

    Help With Circuit

    OK will do. This will give me a negative current source and the calculations you showed earlier will still apply? Are there any limitations to the value of sense resistor that I can use? I'm sorry about all the questions but I was finding it difficult to understand the operation of the...
  14. R

    Help With Circuit

    C N I change the n channel circuit to give me a constant negative current?
  15. R

    Help With Circuit

    Hi guys. Just seen the new circuit. Are there any limitations if I need to alter the sense resistor for different values? Could you explain the calculations for op current. Thanks in advance Raj
  16. R

    Help With Circuit

    Hi guys, I need a negative constant current source. I can't see the corrected circuit. I presume I have to use a p channel for this. What will the circuit look like? Why is my current circuit working? I can't understand, it's starting to get confusing. Thanks in advance Raj
  17. R

    Help With Circuit

    Hi guys, Sorry for the confusion. Steve do you have the new circuit with correction. Thanks for the help with this. Thanks in advance Raj
  18. R

    Help With Circuit

    The circuit has a -0.5v at vin, the source is fed back to the inverting input. fet is n channel d to 0v, inverting input connected to -5V via 10K to allow inverting input to be driven to same potential as vin i.e. -0,5v. the output is taken from the 1M, so -0.5/1M is the current o/p. Note: vin...
  19. R

    Help With Circuit

    i will show the correct schematic, give me 2 minutes
  20. R

    Help With Circuit

    Hi Sorry, it is a n channel mosfet that i have. incorrectly it is a p channel in the diagram.
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