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  1. J

    C programming on PIC16F877A

    what are you predicting, what is your outcome? I agree with steve if I assume like him you want led_1 on then off then led_2 on then off etc... Do all three of the LED's light, or is that your problem?
  2. J

    Power Supply current limiting ???

    Don't solar panels work like wind generators in that the voltage is limited to the clamped voltage, like say a battery bank?
  3. J

    Variable power supply

    How much current do you require? Do you need current limiting? Do you want a linear or switching PSU?
  4. J

    Power Supply current limiting ???

    I think I would have invested in a battery bank instead of a fuel powered generator. I can see the satisfaction in wanting to build something that is hard and complicated. But electricity shouldn't be hard and complicated, just more things to break or go wrong. As steve has already said with...
  5. J

    Power Supply current limiting ???

    Reduce the ripple by increasing your capacitance of the capacitor bank. But be extremely careful, a capacitor bank charged to ~400V is gonna be capable of killing you and your friend in spectacular fashion, Pretty dangerous what you are attempting.
  6. J

    Solar cell, photoresistor and motor -- need help

    Well well well. You gonna need to have a design before you can properly fit the parts to your design. Where is your design? What solar cell? What size motor? Etc. You have given us nothing.
  7. J

    IC 555

    Now I feel dumb for not posting it, I knew it after all
  8. J

    I have issues with MAKE: Electronics experiment 8? (The link may not work so tell me

    link is bad for me :(
  9. J

    How do drive a power mosfet gate

    http://search.digikey.com/us/en/cat/integrated-circuits-ics/pmic-mosfet-bridge-drivers-external-switch/2556427?k=mosfet%20gate%20driver Gate driver IC?
  10. J

    IC 555

    The whole thing is just getting muddled. The OP is starting to ask same questions over again.
  11. J

    thevenin's help

    Guess I will have to go back and re-read thevenin's theorem again. Because I am now lost on what I thought I knew. *shrugs*
  12. J

    Need Proper Schottky Diode of 100 Watt & operating frequency of 10KHz to 50KHz

    Quick search on digikey gave me 5 pages of results that fit the bill. All for high freq.
  13. J

    thevenin's help

    what? How can two resistors in series be equal to their parallel equivalent?
  14. J

    IC 555

    An op-amp can be a comparator but a comparator can not be a op-amp.
  15. J

    Replicating exact battery voltage and current for devices

    Best way to work is with a voltage regulator, cheap easy to use and few external components. Common ones work up to around 1A which should suffice for anything running on batteries. A device will only sink as much current as it needs, having more is always better. :)
  16. J

    Normal/Alternative DC uninterruptable power supply with battery back lighting circuit

    Your board in the picture gives you a good hint how to use the parts together. How one can control the other. A npn transitor needs a positive voltage on its base 0.7V greater then its emitters voltage for its collector-to-emitter junction to conduct. a pnp transistor needs a negative voltage...
  17. J

    Normal/Alternative DC uninterruptable power supply with battery back lighting circuit

    What connector? what type of relay? A relay will either open or close a circuit (mechanically, like a switch) if power is applied to the coil. Vice versa when power is taken away. NC = normally closed NO = Normally open. When the relay is not powered the state of the 'switch' will be either NC...
  18. J

    Normal/Alternative DC uninterruptable power supply with battery back lighting circuit

    Your on the right track. Now a NPN transistor needs 0.7V before it will start to turn on. So you need to figure out the values for your divider to put at the very least 0.7V on the base of the transistor when VCC is 20% below normal. Is that what you had in mind? Where are you struggling to...
  19. J

    Normal/Alternative DC uninterruptable power supply with battery back lighting circuit

    Well haven't you studied the basics of electronics? This seems to me to be an end year project or something? You can use the transistors as switches, but you need to figure out the values of resistors you will use to get it to turn on when the voltage is 20% below normal. You should probably...
  20. J

    Normal/Alternative DC uninterruptable power supply with battery back lighting circuit

    what is this some kind of homework? Who thinks you will build what you want this these parts? When I first read this I was thinking you'd need a boost converter at the very least. Maybe not depends on what your needs are exactly. You will need to spell out exactly what your load is gonna be if...
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