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  1. BobK

    FET switch circuit - is it correct

    You could just make the resistors in the divider 10X bigger. The capacitor across the lower resistor ensures that the ADC in the PIC will get enough current when sampling, assuming you are not sampling at a rate higher that the charging rate define by RC which would come to about 1/200 seconds...
  2. BobK

    laser ablation of PCB resist

    What size are those traces? Bob
  3. BobK

    Can someone help me figure out what i'm looking for?

    Well, you expect wrongly. We often require both of those in order to help someone. Look at some of the other threads in the forum. In any case, you were much less forthcoming than that, you did not say what your project is. If you had said, "I am making an LED flashlight, and I need the...
  4. BobK

    Can someone help me figure out what i'm looking for?

    Why are you so cagey about the function of this thing? If you want one, you must surely know what it does, or at least, what it will be connected to. Why not tell us? Bob
  5. BobK

    FET switch circuit - is it correct

    I am not certain this is your problem, but the problem might be that you are powering you PIC through the voltage dividers. PIC I/O pins have protection diodes to Vcc and Vss. If you supply a voltage that is greater then Vdd on any pin, current flows to Vdd essentially powering the PIC. With...
  6. BobK

    preperation for developmemt

    The first question you need to answer when producing a product is: Why is it better than existing products? From your description of the prototype, it is not. You are not ready to make a product. Bob
  7. BobK

    LED optic sensor circuit

    So the only mystery left is why the IR emitter cannot turn on the phototransistor. I still say you should try higher current, maybe not going all the way down to a 25 Ohm, but may a 100 Ohm resistor. Bob
  8. BobK

    FET switch circuit - is it correct

    Is it in a metal case? I have not seen any in plastic cases without the P in the name. Bob
  9. BobK

    LED optic sensor circuit

    Also, the emitter is rated as 1.3V and 150mA. To get that current with a 5V supply, the resistor would be 25 Ohms. With a 220 resistor you may not be getting a lot of light out of it. Try lowering the resistor. Bob
  10. BobK

    LED optic sensor circuit

    That would indicate that it is a phototransistor and was connected the way you want it. Forgive me if this is a stupid question, but are you pointing the top of the two component as each other? That is the direction in which they emit and absorb light. If you simply put them side by side...
  11. BobK

    FET switch circuit - is it correct

    Unless you had a metal case, you did not have a 2N2222. There are two version of this transistor in plastic TO92 cases. P2N2222a and PN2222a. Look similar right? But they have different pinout. The base is always in the middle but the P2N... has CBE and the PN... has ECB. So you probably...
  12. BobK

    LED optic sensor circuit

    If those are your voltage readings, I think you have the LED and phototransistor reversed. Did you try looking at it with a camera as Kris suggested? Bob
  13. BobK

    PWM output mirror??

    I am being facetious. It thought it was showing a generic switch. Of course we need the full schematic. Of course, if he is using a P MOSFET, it explains why the signal is inverted. Bob
  14. BobK

    LED optic sensor circuit

    Interesting reading the reviews on that Radio Shack product. People disagree on which is the emitter and which is the receiver. I would expect that the receiver is the dark one, since the coloring would be to block visible light and make it sensitive only to IR. But many of the reviewers...
  15. BobK

    PWM output mirror??

    I would guess a finger, since the schematic has a pushbutton switch. Bob
  16. BobK

    Small Circuit needed for New Product Design - Help!

    Not in the area. If I were to do it, I would charge $500 to deliver one prototype PCB (not to a specified size and shape) and the code. Is this in the range you are thinking? Bob
  17. BobK

    3 Simple Questions About PCBs

    Your layout software will typically have the holes correct for whatever component you select, you do not need to specify the hole size separately. For example, if you select a 1/8 W resistor it will have 1 hole size and for a 1W resistor it will have a large hole size. Bob
  18. BobK

    (90-660) volt into (0-277) volt power supply

    Yes, mostly found in Las Vegas. Bob
  19. BobK

    (90-660) volt into (0-277) volt power supply

    Yep, that is why he is still alive after doing a lot of work with electronics. Your question indicates that you might not be so lucky. Bob
  20. BobK

    FET switch circuit - is it correct

    Yep, either way works correctly. If you had disagreed with me, I would have shown the method you used to get the same result. :) Bob
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