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  1. Arouse1973

    How to select proper rating fuse!!

    Depends on the maximum current the citcuit will use. This will effect the type of fuse to use also. If there is a large inrush current then I would go for an anti surge type. Try a fuse with 25% over head to start with and see how you go. Adam
  2. Arouse1973

    Assistance with Transistor Theory

    Well you could wiggle the voltage from say 0.6 to 0.7 volts and wouldn't you get a change in collector current? Adam
  3. Arouse1973

    Assistance with Transistor Theory

    Well the fact that without a voltage you wouldn't have a current would you? So if you increase the current the Vbe would increase. Apart from resistance changes, current is a direct result from applied voltage. Voltage is the controlling factor in it all. If you control the current you are...
  4. Arouse1973

    Assistance with Transistor Theory

    Well I think we can do both, drive it with a voltage source or a current source. Only one of these methods shows the true controlling factor. Adam
  5. Arouse1973

    Assistance with Transistor Theory

    Yes I like that one Ib is an indication of collector current. Adam
  6. Arouse1973

    Assistance with Transistor Theory

    Page 63 of "The Art Of Electronics" "Property 4 gives the transistor its usefulness: A small current flowing into the base controls a much larger current flowing into the collector"
  7. Arouse1973

    Assistance with Transistor Theory

    Thanks Ratch. Adam
  8. Arouse1973

    Assistance with Transistor Theory

    Yes I agree with that. Adam
  9. Arouse1973

    Assistance with Transistor Theory

    I am only trying to portray where I think this base current control idea came from. I think I am doing a pretty bad job :) Others haven't come up with any other ideas, it was the best I could think off. For me I don't think about the method I am using but if I was to explain it to someone else...
  10. Arouse1973

    Assistance with Transistor Theory

    Yes right Vbe will take care of itself. This is why I think people forget about Vbe and say let the base current do the work. So for them they are controlling the collector current using the base current. The fact that Vbe will change a small amount is irrelevant to them but a necessity for the...
  11. Arouse1973

    Assistance with Transistor Theory

    Hi Ratch Yes I did read this and very interesting it was. The example I gave was trying to portray how some people may design a circuit using a current source. If I change this a bit then and say fully switch the transistor on assuming a min HFE of some amount, say 10. Then I set the base...
  12. Arouse1973

    Assistance with Transistor Theory

    Hi Lvw. I don't think I said that the current control method is the best for practical circuits. I said it's sometimes easier to work with the current control method. The second example didn't have the POT because of the current source, it does not matter that it's an ideal current source. A...
  13. Arouse1973

    Assistance with Transistor Theory

    Hi Lvw One example I can think of is this. I have a transistor which I don't have the data sheet for, all I have is a meter that measures HFE. I want to set the collector output to half supply. So I add a variable POT for the base resistor and connect an ammeter in series with the base...
  14. Arouse1973

    Assistance with Transistor Theory

    Hi Lvw I think you hit the nail on the head with regard the word Control. People may interpret this differently to the word operation. I am not disagreeing with you in the fact that Vbe is the deciding factor in how much current will pass through the transistor. It's just sometimes easier to...
  15. Arouse1973

    Assistance with Transistor Theory

    I agree, this type of discussion is priceless. With so many great minds coming together in such a debate. It may irritate some people but then they don't have to get involved do they. But I bet they keep an eye on this thread though.
  16. Arouse1973

    Assistance with Transistor Theory

    Here is my attempt, it maybe a simplistic method but it has worked for me many times. This is how I do it and it gets me close enough that all I would need to do is replace the one of the bias resistors with a variable resistor once common values had been chosen which allows me to trim anything...
  17. Arouse1973

    Need Help Understanding Hi Current Add On For LM78XX

    Ok merry xmas to you and your family.
  18. Arouse1973

    What is a low input current line receiver

    No probs
  19. Arouse1973

    Assistance with Transistor Theory

    I'll do an example after xmas of how I do it. All the best Adam
  20. Arouse1973

    Need Help Understanding Hi Current Add On For LM78XX

    Yes the diode discharges any output capacitance when the power is switched off. Some people do some people don't. I don't personally as most of the time I don't have that larger capacitance on the output. Are you thinking of PTC or NTC. PTC is used for over current protection and NTC is used...
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