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  1. chopnhack

    Rain Sensor Status

    I have seen the 0.1 and 1μF caps placed in parallel with the input and output respectively on a few datasheets. Don't C1 and C4 accomplish the same thing despite them being of larger value? Thanks!
  2. chopnhack

    Rain Sensor Status

    Post 37 - listed as C1 Dave, what is the purpose of the small capacitors in parallel that you asked me to add?
  3. chopnhack

    Rain Sensor Status

    Yes, that is why Harald recommended the use of capacitor fed supply then use a voltage regulator to further drop and regulate. That is what the capacitor is for. My only problem was that to give a 11-12v supply to the regulator required a 100μF cap. I couldn't find any ceramic type with a 50v...
  4. chopnhack

    Rain Sensor Status

    What would you recommend for the C3, the first cap that the AC runs through? I tried other values, but 100uF seems to be the value that will give me adequate input voltage to the regulator. I am having a hard time finding that size though...
  5. chopnhack

    Rain Sensor Status

    On actuation the voltage from the transformer only fluctuates to 28.6VAC while the solenoid is energized. The system spends most of its time in the unenergized state so designing the system based on 29.2VAC seems the way to go. So I still need to know if I was correct about R4: The input is...
  6. chopnhack

    Rain Sensor Status

    I had a hard time finding a model for the LM7805 in LTSpice - ended up on youspice.com and found one made by LT! For the values below I get a clean, fairly ripple free 5Vdc output from the v-reg. The input is around 11.8V with 33mA across R4. Assuming I applied Ohm's law correctly (P=IV)...
  7. chopnhack

    Part identification

    Maybe its designed to respond to a specific spectrum of light?
  8. chopnhack

    Part identification

    Howdy neighbor :-) I had seen an instructable(?) some time ago how they were making cheap microscopes with a lens and a cheap digital camera... pretty cool. If I had to guess, I would say it looks like a SMD led - take it for what its worth, I am probably wrong ;-)
  9. chopnhack

    Rain Sensor Status

    Thank you Harald, it looks like a winner :)
  10. chopnhack

    Rain Sensor Status

    Excellent! That should be easier to source. I have seen non-polarized aluminum caps, are those ok? Or are they miswritten. I found a ceramic on Digikey rated at 50V non polar that looks good. Good point, just because the simulation shows a stable result doesn't mean it will remain static as...
  11. chopnhack

    Rain Sensor Status

    It got cut off on the bottom, but 3.3v and 33mAis the output across and through R4 if I use 4.7μF for C1, C2 1000μF and 100Ω for R4. The schematic shows 2200 - I was playing with values to see what they do and forgot to change it back. What are your thoughts on this?
  12. chopnhack

    Rain Sensor Status

    The VDC looks pretty stable there! I didn't think it would be because of the source... Am I correct in assuming then that with a X2 or Y2 rated cap for c1, I can build a suitable supply for the two transistors and leds without a regulator?
  13. chopnhack

    Rain Sensor Status

    I had 7805's on hand so that seemed the easiest way to produce the 5v. Why 5v? - I figured with two LED's I might need the Vdrop - but now realize I would only need about 3v since they would never be in series. I had given thought to a capacitor fed p.s. - but remembered that the wall adapter...
  14. chopnhack

    Rain Sensor Status

    I need to clarify this, I just couldn't find an appropriate component in eagle. The input is really 29.2VAC as measured on my DMM. It's coming out of a 24V wall adapter.
  15. chopnhack

    Rain Sensor Status

    I thought chokes and inductors were synonymous? Shame too, I don't seem to find an assortment of toroidal style or coil style inductors on e-bay. I did find the resistor type. Will this type not work at all? Thank you No worries, I do worse... have you seen some of my schematics? :eek::p
  16. chopnhack

    Rain Sensor Status

    eep... LOL I will update the schematic, its supposed to read LM2576 - switch mode supply.
  17. chopnhack

    Rain Sensor Status

    If I am reading this chart correctly, the inductor that is needed for the basic regulation circuit is dictated by the current usage of the circuit and Vinput. If I have about 28v coming into the circuit and the circuit consumes about, maybe 100mA(unsure?): Would I need a 1000μH inductor? What...
  18. chopnhack

    Rain Sensor Status

    LOL I get into too much trouble with just two transistors! Thank you Harald, that is an excellent post, but above my comprehension at the moment. I ordered some LM2576, about 45 cents US each.
  19. chopnhack

    Rain Sensor Status

    Yes, I found one, LM2576. Any other suggestions?
  20. chopnhack

    Rain Sensor Status

    Can anyone recommend an inexpensive switching regulator?
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