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  1. Arouse1973

    Transistors

    Well I think yes because I have read somewhere that people have done this on the edges of capacitors but the field is very very small. Adam Dc is in one direction so I suppose until it reaches maxima it is in one direction but then changes direction as it passes through 0V to some minus value...
  2. Arouse1973

    Transistors

    The generally accepted term "Electrical Current" is the flow of electrons. This has been wildly used for many years but Electrical Current can happen without electrons. Example is the electrical current in ice is produced by + ions or it can be both electrons and ions like in a spark. So another...
  3. Arouse1973

    Transistors

    Fair enough Steve.
  4. Arouse1973

    Transistors

    Its not a true current in the sense of current as we know it. It is due to the changing electric field inside a dielectric it is not the flow of charges around a circuit. But it can also have a localised magnectic field. Adam
  5. Arouse1973

    Transistors

    1) Yes I would say that is correct, like charges repel. 2) As I see it the electrons are already there in the metal. This sea of electrons is what makes metals shiny. When you pull an electron out of one plate you now have upset the balance. This can't be aloud so another electron from the other...
  6. Arouse1973

    Transistors

    And I suppose we should also say a capacitor stores electrostatic potential energy. Or just electric potential energy. As we know energy has many sources. Defining which ones is also helpful. Adam
  7. Arouse1973

    Transistors

    :) I knew what you meant. Adam
  8. Arouse1973

    Transistors

    I thought a capacitor stored only energy and not charge. The capacitor will always have the same amount of charge it's just one plate might have more than the other. I thought the charge was there right from the start. adam
  9. Arouse1973

    ground pour under component

    We do this all the time when we design PCBs. You are referring to a power plane of some sort I guess? If you are having your PCB manufactured professionally and you have solder resist put on as a protective coating then this should be fine. Although more expensive It is quite common practice to...
  10. Arouse1973

    Stability analysis for hysteretic switched mode LED driver?

    I don't quite follow. You don't produce phase and gain margins the gain margin is the amount of gain you can add to lift the 0dB point to the same frequency as the -180 degree crossing point. Phase margin is the difference between the actual phase and -180 degrees. An open loop opamp can be...
  11. Arouse1973

    Transistors

    Just out of interest I thought I would have a look through some of my many books to see if I could find one to recommend to the OP that has good information on transistors. The Art of Electronics (Second Edition) page 63 states “A small current flowing into the base controls a much larger...
  12. Arouse1973

    graph of time constant rc network

    Nice one :)
  13. Arouse1973

    super capacitor capacity?

    Maybe because he want's to have a play with electronics. Adam
  14. Arouse1973

    graph of time constant rc network

    Yes and that is because e^-1 = 0.36 which is 36% when -Tau/RC =-1 I thinks that's right Steve? Adam
  15. Arouse1973

    Happy Easter !

    And you mate LOL Nice egg by the way Yum! Adam
  16. Arouse1973

    super capacitor capacity?

    Because the TX coil will be loaded by the circuit and it is not regulated I just added 20V to give a bit of head room for the current. It might be lower. The example just gives you an idea of what is needed to receive 20V on a coil 3m away. It is not the absolute values for your circuit. I could...
  17. Arouse1973

    super capacitor capacity?

    He is something rough I had a go at working out. It is for two un-tuned coils separated by 3m. Shows the amount of current needed to induce a certain voltage in the secondary coil. This is approximate and would work better if the two circuits were tuned. Thanks Adam
  18. Arouse1973

    super capacitor capacity?

    Yep Ok I'll have a look at something for you.
  19. Arouse1973

    super capacitor capacity?

    Hello Divedeep. All I would like to add to Kris's great reply is depending on the manufacture of the super capacitor you may have to consider leakage current. Some of the capacitor might have a higher leakage current than what your circuit draws on average. Also charging current will need to be...
  20. Arouse1973

    PCB Software

    Not sure it's quite exspensive but IF like it because you can start of with the basic package and then add on bits when you need them. The demo has no time out so you can do small PCBs for free. Not sure how many nodes it gives you, might only be 100 or so.
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