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transisor sl100

Discussion in 'Homework Help' started by domz15, Aug 5, 2011.

  1. audioguru

    audioguru Well-Known Member Most Helpful Member

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    You forgot to show us the schematic of the project and forgot to tell us what size and type of battery it charges.
    So we don't know what transistor you can use.
    We also don't know which transistors are available in your country.
     
  2. Ziddik

    Ziddik Member

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    hi domz..

    If u can post the schematic of your project then experts can recommend u a transistor and will notice you if there is something wrong in your schematic
     
  3. domz15

    domz15 New Member

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  4. dave

    Dave New Member

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  5. mvs sarma

    mvs sarma Well-Known Member

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    you get 2SC1061 or BD139 cheap enough. try to use one
    with proper connections
     
    Last edited: Aug 10, 2011
  6. domz15

    domz15 New Member

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    thank you sir :)
     
  7. domz15

    domz15 New Member

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    do you think BC548, BC327 or 2N4401 will work?
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

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    No, they will burn out or melt. Post #24 recommended suitable replacement power transistors.

    The extremely old circuit from that website in India is for charging a very old Ni-Cad battery, not the Lithium battery in a modern cell phone.
    Here in Canada, cell phones have not used a Ni-Cad battery for about 15 or 20 years.

    Cell phones have the special charger circuit for their battery built into the cell phone. The power supply for it is wrongly called a charger.

    Does your cell phone have an antique Ni-Cad battery or a modern Lithium battery?
    Do you want to charge the battery while it is in the phone or do you want to charge an extra battery that is not in the phone?
    A Lithium battery needs a modern charging circuit that is completely different from this very old circuit.
     
  9. domz15

    domz15 New Member

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    i want to charge a lithium battery while it is on the phone.. do you have a circuit of that charger?
     
  10. mvs sarma

    mvs sarma Well-Known Member

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    be sure that you won't spoil your face. with the type of schematics , if you experiment charging Li-ION etc batteries. You are likely to get damaged physically.
     
  11. domz15

    domz15 New Member

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    aw.. hmm do you know a circuit that charge a lithium battery? and it automatic cuts off the charging process when the battery if fully charged?

    thank you :)
     
  12. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Most charger circuits for lithium batteries use an IC that is set to charge the amount of mAh of the battery. The IC correctly refuses to charge a battery that is already charged because it senses it. A lithium battery that is being over-charged can catch on fire.
    It charges the battery at the correct amount of current because if the current is too high then it can catch on fire, and turns off charging when it detects that the battery is fully charged because a lithium battery that is continuously trickle-charged can catch on fire.

    Some lithium battery charger charger ICs can power the phone at the same time it charges the battery.
     
  13. mvs sarma

    mvs sarma Well-Known Member

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    Many a time, forbid me, half knowledge added with over confidence is dangerous.
    I understand your enthusiasm. best to use available chargers in market or best is to use what is supplied with phone.

    Designing a circuit for a purpose is different from aping a pre published one.

    Try to Understand Audioguru and better look for some other design with a suitable chip designed for that purpose.
     
  14. domz15

    domz15 New Member

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    thanks for your help :) I appreciate it :) what type of IC it is?
     
  15. audioguru

    audioguru Well-Known Member Most Helpful Member

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    A battery charger IC is called a Battery Charger IC and most semiconductor manufacturers make them. Most of them allow you to select the type of battery (Ni-Cad, Ni-MH or Lithium), how many cells in series and the amount of charging current.

    EDIT: You want to charge the battery in the phone and the phone already has a battery charger circuit in it so why do you want to make a battery charger?
     
    Last edited: Aug 11, 2011
  16. Ziddik

    Ziddik Member

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    i have seen LM358 ic in a cellphone charger with a bunch of LEDs That indicates different states of charging process (ie.full,charging,.etc
     
  17. domz15

    domz15 New Member

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    My project is a cellphone charger by using a 12V, 5watt solar panel.. my professor wants me to build a circuit outside the cellphone that will automatically stop the charging process when the cellphone is fully charged?
     
  18. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Doesn't your cell phone already have a charger circuit inside?
    Doesn't the charger circuit inside your cell phone already stop the charging when it detects the battery is fully charged?
    Then doesn't your professor want you to remove the battery from the phone and charge it with your own charger circuit that you will make?
    Can you buy modern Western parts in your country? Or will you make a charger with hundreds of parts that are inside a modern battery charger IC?

    Does your cell phone use a very old Ni-Cad battery or a modern new Lithium-ion or modern new Lithium-Polymer battery?
    If your cell phone uses a very old battery then does the battery still work?
     
  19. Ziddik

    Ziddik Member

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    i think u should search such kinds of circuits on internet.
     
  20. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Why doesn't the professor do his job and teach about these kinds of circuits?
     
  21. domz15

    domz15 New Member

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    does lithium batteries automatic stops the charging process when fully charged?
     

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