Recent content by Enac

  1. Enac

    Constant current source for a low Ohm load

    If your resistor is really a constant 20 ohms, then you only need a variable voltage source with a range of zero to 2.4V, which is what Indulis's circuit does (although it may oscillate). A current source provides constant current independent of the load. Does your load vary? If so, I can...
  2. Enac

    Pool water level stabelizer

    Google "float switch". I found some inexpensive ones, and plans for a homemade one.
  3. Enac

    60VDC 10A Power supply design.

    Is there some reason you can't use a switching regulator? A 10 amp linear regulator is bulky, expensive, and hot!
  4. Enac

    Electricity Meter

    Do a Google search on "kill-a-watt". You can buy one for around U.S. $20 - $30. Of course, if you really want to build one, you could learn a lot.
  5. Enac

    hm

    I use Linear Technology's LTSPICE/SWITCHERCAD III. It's totally free, but is not easy to use unless you have a good understanding of Spice.
  6. Enac

    Timed resistor

    How about a digital pot driven by a variable-frequency oscillator (555)? Maxim, or other mfrs, may have other parts that will work as well or better. Google (digital pot".
  7. Enac

    common-mode??

    Great explanation, AG!
  8. Enac

    Voltage level shifting

    I see that now. I'm sure glad I pre-apologized for missing it! :)
  9. Enac

    Voltage level shifting

    Forgive me if one of you guys already suggested this solution. All you need is two equal-valued resistors and a rail-to-rail I/O op amp. One resistor (Rs) goes from +5V to the inverting input. The other (Rf) goes from the inverting input to the output. The 2.5V-5V input signal goes on the...
  10. Enac

    led powered by a/c How To?

    The 1uF cap needs to be nonpolarized.
  11. Enac

    LM317 Variable power supply

    MP, the National datasheet says the typical minimum current is 3.5ma, but the maximum minimum current (sounds like an oxymoron) is 10ma. Whose datasheet are you using?
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