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  1. (*steve*)

    Is there any particular reason this won't work? Thanks

    The last one is wrong. You are right on the resistor questions, but you need to go back and look at what capacitors do again.
  2. (*steve*)

    Buck converter help

    I recommend you place a zener diode across the generator with a voltage a little under the max voltage of the buck converter. Whilst under load, the output from your generator should remain lower. If you ever expect to run the generator without a load you may be better off with a series...
  3. (*steve*)

    Dr Who's K9 circuit help...

    A simple way of choosing the 4 lights to turn on is to start with an array of 12 integers (they will have indexes 0 to 11) initialized to the numbers 0 to 11. Each time you want another set of lights you loop through the first 4 elements of the array (0 to 3) and generate a random number in the...
  4. (*steve*)

    Wireless Inductive Coil - How does the transistor make it work ?

    Google "blocking oscillator" As shown it will probably destroy the transistor in short order.
  5. (*steve*)

    Dr Who's K9 circuit help...

    The arduino has its own random function. Yes it's pseudo random. All you need is a resistor in series with the LED.
  6. (*steve*)

    How do constant current loads work and how to make one

    Your design will be different in some respects: You'll need a far larger heatsink and probably multiple mosfets. You won't need a 10 turn pot, a simple 1 turn pot will be fine. The sense resistor will need to be smaller, perhaps 0R2 You may need a voltage reference. What do you plan to power...
  7. (*steve*)

    How do constant current loads work and how to make one

    I think you should first look at this video so you understand the concepts and then we can talk specifics about the design you'll need.
  8. (*steve*)

    How do constant current loads work and how to make one

    And the smallest current? Would you want to be able to easily and accurately set it for 1mA, or would a couple of hundred mA be practically the smallest current you'd require?
  9. (*steve*)

    How do constant current loads work and how to make one

    Ok, so they are the maximum ratings, what is the minimum voltage across the input that should allow it to operate at maximum current? What are the typical current you'd want it to operate at -- especially the lowest?
  10. (*steve*)

    Is there any particular reason this won't work? Thanks

    OMG! the 2N2222 relaxation oscillator. That poor 2N2222. I hope you gave it a good funeral. Perhaps you should have started with something that involves actual transistor action and doesn't destroy the device.
  11. (*steve*)

    Is there any particular reason this won't work? Thanks

    I don't know the book, so I have no idea. However the indications are that you may have read earlier chapters but not understood them. Does the book have any quizes? Do you know what resistance you get if a 10k and a 1 k resistor are in parallel? If a 10k and a 1k resistor are connected in...
  12. (*steve*)

    Is there any particular reason this won't work? Thanks

    I see nothing on your blog about capacitors. And the first page on transistors is riddled with misconceptions.
  13. (*steve*)

    Capacitor charging

    Well, if we had any idea what the "right side 2k resistor" was. It's also probably there for a reason. Maybe to prevent something from being overstressed?
  14. (*steve*)

    Is there any particular reason this won't work? Thanks

    Maybe start a few chapters earlier than that...
  15. (*steve*)

    Is there any particular reason this won't work? Thanks

    In the case of R4, there's a cap in the way so that won't work (same for R2). There is very unlikely to be a single fault given your level of knowledge. Electrons flow that way, but by convention we assume the opposite. This also means that all the arrows point in the right direction :-)...
  16. (*steve*)

    Floating pins on Microcontroller

    However, the point is that it has some pins that are always inputs. From memory the serial input pin is one of these. The added complication I'd that it is used by the bootloader to initiate downloading a program. If it is not properly terminated the bootloader can decide it is being...
  17. (*steve*)

    Charging/Discharging circuit for multiple 18650 batteries

    The key word is"I". The university presumably don't want you to outsource your design, and we are not going to do your homework for you. What research have you done on lithium battery charging requirements and cell protection? You've mentioned "fast" charging several times. How much energy...
  18. (*steve*)

    Charging/Discharging circuit for multiple 18650 batteries

    Why are you doing something for your final project that is unrelated to your course? Why are you doing something for your final project that you hardly have the first clue about? By the looks of it we'd need to do a huge about of the design work for you. Can you give us the name of your...
  19. (*steve*)

    Is there any particular reason this won't work? Thanks

    R4 is possibly on the wrong side of the capacitor.
  20. (*steve*)

    Floating pins on Microcontroller

    My mistake. I thought a picaxe was involved. It has some pins which are always inputs.
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