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  1. EdwardM

    12vdc->9vdc

    Hi Scott my first thought is that you could take a connection from one of your 12v batteries and plug it in to the garage door button unit.  I suspect that the difference in voltage would not be significant, ie, 12/9*100 or roughly 30% more, it really depends on the design of the unit and...
  2. EdwardM

    Optical guitar pickup

    Hi Nikolas try here, Fairchild is just one of many manufacturers of this kind of product Cheers Ed Added: here's a good site and the Google search I used
  3. EdwardM

    Optical guitar pickup

    Hi XYZ without going too deeply into the various points you raised, could you explain a bit more about your assertion... Ed
  4. EdwardM

    Humanoid with artificial intelligence and emotions.

    Hi Alun looking at your original post, I can't help feeling that we also have the perennial problem that many of the people who post here don't have English as a first language and it is often difficult to determine, for me at least, what the question really is... I'm afraid I'm of the school...
  5. EdwardM

    2N3055 Vce(sat)

    sauna, luuverly ;D as you've seen the vce(sat) of the '3055 equates in resistance terms to 10 times greater than that of the BUZ11, however there is a slight trade-off in that the gate-source capacitance of of the BUZ has to be charged up before anything useful can be done and this means power...
  6. EdwardM

    2N3055 Vce(sat)

    Hi Bjorn mosfets and transistors are quite different as you've seen, but in a switching configuration you could equate the two parameters, ie, Vcesat = 1.1v@4A is equal to a resistance of 0.28ohms and Rds(on) = 0.03ohms Didn't Liverpool do well Nothing foolish about the thoughts Ed
  7. EdwardM

    Model Elevator Control Circuit - PLEASE HELP!

    Hi Dan sounds like a fun project. To be honest, if I were designing this, I'd use a combination of a stepper motor/gearbox and microcontroller.  The stepper would give you precise control over speed (presumably moving at 1/12 speed?) and the microcontroller would allow the use of some...
  8. EdwardM

    Pressure switch output??

    Hi John circuit as shown below. To reiterate, max current into load is 80mA which aint much so you may need to drive a small relay or transistor first to make your solenoid work. (If you need help with that, come back) Best of Luck Ed added second drawing just in case
  9. EdwardM

    Want to use LED Dot Matrix Board

    Hi one of the ways of driving a LED matrix is to use dedicated IC's from various manufacturers, for example: http://www.maxim-ic.com/appnotes.cfm/appnote_number/1033 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1339 and this one http://noisybox.net/electronics/LED_sign/ Best of Luck Ed
  10. EdwardM

    Pressure switch output??

    Hi John, you haven't said which SMC switch it is but looking at some of them it appears that the output current available is less than 80mA which means that you could drive a small relay (solenoid) and use its high current contacts to drive something bigger, it really depends on which switch...
  11. EdwardM

    Pressure switch output??

    Hi can you post a data sheet for the DP switch?, it may be that there is insufficient current avaiable or something else.  If you can provide a sketch of your circuit, that would be helpful too Best of Luck Ed
  12. EdwardM

    3-Axis Stepper Controller

    Hi GreekPIC I've been promising myself for years that I'd build a CNC machine  ;) real soon now. Apologies if you've already done so but could you post a picture of the mechanical aspects of the machine? Thanks Ed
  13. EdwardM

    3-Axis Stepper Controller

    Hi GreekPIC this link will give the the complete answer as to why the DVM reads anywhere between 470k and 2.7M Ohms http://www.pge.uk.com/PGE/pdf/KNB153x_R.pdf Ed
  14. EdwardM

    boost converter

    I didn't wait long enough for my latest post to upload...  :P and it got lost ??? What I said was that the output from the transformer is AC.  And the action of the diode is to provide both DC and secondarily, a nice word for this time of night, to prevent the capacitor discharging back through...
  15. EdwardM

    why output voltage of LM317 decreases?

    Hi Shahriar the first thing I can see is that R1 isn't really doing anything apart from being a current dump for the bridge rectifier.  If you want to limit the inrush current to the reservoir capacitor then a resistor should be placed in series with the capacitor. It may be that most of the...
  16. EdwardM

    boost converter

    Hi Alun Am I missing something, the output is pulsed DC...? are we at cross purposes? Ed
  17. EdwardM

    boost converter

    Hi All hopefully to make it clear... Ed
  18. EdwardM

    What will it do if I...?

    Hi LegendBreath I'm afraid my Vic has gently rusted out in the garage, maybe there's some way of recycling it as a doorstop, ah! technology moves on, in an odd sort of way I'd be happier playing with my Vic, PET, Dragon, Atari or Sinclair (Yes, i've still got them all) than Visual Studio .NET...
  19. EdwardM

    What will it do if I...?

    Hi LegendBreath this takes me back a bit.. but according to websearch Yes, they are identical.  The 6507 package was created strictly to save space on the PCB, in those days it did not make sense to create a new die and mask for such an "improvement" since this was much more expensive than the...
  20. EdwardM

    boost converter

    Hi Alun * Absolutely * ;) Ed
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