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  1. CDRIVE

    How to control the speed of a 24vdc pump from circulating water temperature?

    Let us know when the parts arrive. some experimentation will be needed. Chris
  2. CDRIVE

    How to control the speed of a 24vdc pump from circulating water temperature?

    Both Alec's and my schematic develop the ~ 0 - 5V the same way. The Pots are wired as variable resistors (Rheostats) and the Thermistor is wired in series with the Pot. This circuit constitutes a Voltage Divider. As the Thermistor's resistance changes it produces a voltage change measured from...
  3. CDRIVE

    How to control the speed of a 24vdc pump from circulating water temperature?

    Stu, that description nearly had me fooled into thinking it was authored by an English speaking individual. That is until I reached the description of how to replace the Pot with a 0 - 5V input. It's Pigeon English at it's best. o_O The Input resistance of the control pin would have been nice to...
  4. CDRIVE

    Serial port communication

    You seem to have only a vague idea of the various building blocks that could be used to complete this assignment. I say "assignment" because some of your replies seem to indicate that this is a class assignment. Regardless of that this image may help you visualize at least one possible method...
  5. CDRIVE

    Frequency dependent current controlled voltage source in Pspice

    This link may help you. http://www.ecircuitcenter.com/AboutSPICE.htm Chris
  6. CDRIVE

    Frequency dependent resistor in PSpice

    Ha, I know that this is not what you meant but attempting to use a wire-wound resistor as a 50Ω RF Dummy-Load comes close to fitting the definition. :D Chris
  7. CDRIVE

    Potentiometer Value and Rating?

    :confused: Are they supposed to do that?:rolleyes: Hey, if they did we wouldn't have these "Memory Lane Component" threads! :p BTW, I probably have one (or more) of those old 1Ω heaters buried deep in my storage bay. Problem is; to find anything in that tomb it requires getting tanked just to...
  8. CDRIVE

    Potentiometer Value and Rating?

    I agree but I can't remember an application where they were actually wired and used as a POT. All the applications that I remember found them wired and used as a Rheostat. They dissipated enough heat to damn near be considered a heating element! :D Chris
  9. CDRIVE

    How to control the speed of a 24vdc pump from circulating water temperature?

    It would be quite straight forward but would require some experimentation to select the Thermistor as well as set the Trimpot to calibrate it. All of the Ebay listings utilize a Pot to adjust the PWM but some incorporate an additional External (Voltage Controlled) Input port. You will probably...
  10. CDRIVE

    Using an oscilloscope without a probe. Good or bad idea?

    The grounded scope issue has been a bugaboo since it's inception. Precisely for the reason you posted the topic.. "Current Measurement". Because scopes are grounded it necessitates that one end of the current shunt be connected to ground. Consider this scenario: You're working on a transmitter...
  11. CDRIVE

    Convert constant +12V to pulse

    There are times when a simple (series wired) capacitor will suffice to convert a steady state voltage to a pulse. The pulse will be generated on the leading edge of the control voltage when it switches from 0V to (in your case) +12V. Other options would be a Monostable Flip-Flop that can be...
  12. CDRIVE

    How to control the speed of a 24vdc pump from circulating water temperature?

    In the event that your only option is a DYI solution you can start Here On Ebay. This particular PWM LISTING includes an external control input option that can be interfaced to a thermostat circuit. Just about any 8 pin uC could handle the Temp to PWM control part of this project. My personal...
  13. CDRIVE

    Does electron die?

    Steve, seeing Kris' and CocaCola's name in the same breath made my heart sink. Please tell me I'm wrong but after reading this I realized I haven't seen a post from CocaCola for quite some time. I did search and found this thread...
  14. CDRIVE

    Woodwork machine playing up

    Hey Ed, do you still have 10 fingers? :) Chris
  15. CDRIVE

    Does electron die?

    Your signature is most definitely befitting. Hey, whatever floats your boat. Chris
  16. CDRIVE

    Does electron die?

    Personally, though the term "pressure" may not be an appropriate term to describe Voltage, it's about as good an analogy as can be found when teaching basic electronics. I often used plumbing concepts to convey Ohms Law relationships of E, I & R. Students sometimes need a tangible reference to...
  17. CDRIVE

    Does electron die?

    I think I love this thread! Chris
  18. CDRIVE

    looking for feedback on feasability of this idea...

    I'll second that. ;) Chris
  19. CDRIVE

    Ohm resistance controller

    Oops this topic may be treading on thin ice. I'll leave that decision to the mods and let others test the ice. Chris
  20. CDRIVE

    Convert uneven pulses

    That answers my question and confirms that debouncing should be included in the uC code. Chris
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