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  1. BobK

    1650w electric conversion

    As I understand it, those transformers you see on the poles are center-tapped 220V output transformers with the center tap going to ground, giving you two phases 180 degrees apart. Bob
  2. BobK

    1650w electric conversion

    Hey, what is the worst it can do? Kill someone and burn the house down? Well, yeah. To the OP. I would contact a licensed electrician for this. Bob
  3. BobK

    Understanding PWM with PIC (assembly)

    By subtracting 99 from it and checking status: incf CCP2RL, f movlw .99 subwf CCP2RL, w btfss STATUS, Z goto not_hit_99 goto hit_99
  4. BobK

    Joule Thief Is Not Working

    Most likely, by changing its frequency and amplitude! They are very uncritical with respect to the transistor's properties. Bob
  5. BobK

    Multiple Inputs/Outputs transmitter

    Not sure what you mean by that. These transmitters are usually set up to transmit serial binary data, not analog, if that is what you mean. Bob
  6. BobK

    1650w electric conversion

    I don't see any reason why it would not work in a 220V U.S. outlet, unless the ground is connected in the appliance to one of the phases, but that seems unlikely and illegal. By the way, the U.S. household system is 2-phase, not 3. There are two "hot" lines that are symmetric around the...
  7. BobK

    Joule Thief Is Not Working

    About 66 KHz on the one I built. Bob
  8. BobK

    Lighting Galaxy Quest Ship...Have magnet question

    And worse yet if he had inhaled them. They are supposedly worse for you than asbestos fibers. Bob
  9. BobK

    how to distribute voltage locally on a surface?

    Even if there was, then how could it change from one pattern to the next? I think you are stuck with 9 different voltage sources. Bob
  10. BobK

    Understanding PWM with PIC (assembly)

    Whoops, I did not look at you code very well. The way you are testing for zero will not work. The Z bit is in the STATUS register, not in CCP2RL. You can use: decfsz CCP2RL, f goto Blarg movlw .99 movwf CCP2RL goto Blarg Bob
  11. BobK

    Joule Thief Is Not Working

    I have made a Joule thief myself with a similar sized toroid, but I had, if I remember correctly, 22 windings for each coil. I believe you do not have enough from your picture. Bob
  12. BobK

    Lighting Galaxy Quest Ship...Have magnet question

    The carbon nanotube comment was strictly tongue-in-cheek. Sorry, I should have included a smiley :) Bob
  13. BobK

    Watts equation

    Yes, it changes very rapidly, from too much to none. In other words, the light bulb blows out. If the bulb was designed to work on 220V, it will use half the current to make 100W as one designed to run on 110V. There are devices (for example most laptop power supplies) that will run on...
  14. BobK

    Understanding PWM with PIC (assembly)

    Yes, you can do: decf CCP1RL, f To subtract one from the register. I would suggest that you step through your program with the MPLAB simulator at this point to make sure it is doing what you expect it to do. Bob
  15. BobK

    Understanding PWM with PIC (assembly)

    You might need a BANKSEL before the move to CCPR2L, depending on what Delay2 does with bank selection. Other than that, I see no problems with the code. Bob
  16. BobK

    LED Response Time

    The sensors mentioned by shumifan can actually go up to 40m and in a normal sized room, you can point the sender in any direction and the receiver will pick it up by reflection. But the max data rate of these would be a few K bits per second, since they require about 10 cycles to lock onto the...
  17. BobK

    PWM to Sine Wave Converter

    Yes, that is the point. PWM means Pulse Width Modulation. The width of the pulses changes. PPM means pulse position modulation, where the width of the pulse stays the same but the space between pulses changes, which is what your signal looks like. Where does the signal come from? Bob
  18. BobK

    LED switch wiring

    It does say LED, if so, they probably use a capacitor to reduce the voltage, or else the switch would get quite warm. Lets see, 220V at 20mA = 4.4W, so I doubt that it is an LED with a resistor. Edited: on the other hand, it does not say AC, but maybe they are assuming that. Bob
  19. BobK

    Help with simple LED switch project design

    Lighted switches usually have the resistor built in. If you don't mind sacrificing one of switches, try with no resistor and a multimeter hooked in series to measure current. If it reads around 20mA, it does not need a resistor. If it goes flash and quits, it needs about a 390 Ohm resistor...
  20. BobK

    Understanding PWM with PIC (assembly)

    PR2 tells you how many counts in the PWM period. If the CCP is clocked at 1MHz and you set PR2 to the max of 255, you will get PWM period of 1M / 256 = 3906 Hz. You the set the duty cycle in CCPR1L to anywhere between 0 and 255 for 0 to 100% duty cycle with a resolution of about 0.4%. You can...
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