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need data sheet and/or replacement for SL100 transistor

Discussion in 'Datasheets, Manuals or Parts' started by fgutierrez, Feb 5, 2003.

  1. mneary

    mneary New Member

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    2N2222 would do a good job in your circuit, but change R5 to 3k3 ohms.
     
    Last edited: May 14, 2009
  2. hotwaterwizard

    hotwaterwizard Active Member

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    It looks like they just use it to drive the Relay. Try using the relay Driver circuit from this one that I already posted and use the rest of the circuit from your diagram.
    [​IMG]

    the new circuit would look like this,
     

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    Last edited: May 15, 2009
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The very old SL100 metal-cased transistor has a load of only 12V/200 ohms= 60mA. Any little NPN transistor can drive it if the base current through R5 is increased a little.
     
  4. dave

    Dave New Member

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  5. QAISAR

    QAISAR New Member

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    sir i know these circuits are same.only one difference is present in my circuit i.e
    when the water doesnot com from the well or dry.circuit will beep.and alert us.
     
  6. hotwaterwizard

    hotwaterwizard Active Member

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    If you look at the Diagram Close I modified the circuit you originally posted and removed the SL100 Transistor and replaced it with the drive circuit from the other diagram.
    The yellow one now has a BC337 instead of the SL100 and BC548 both are gone from the schematic and I changed the resistor value of R4 and R5 is gone.


    [​IMG]
     
    Last edited: May 16, 2009
  7. mneary

    mneary New Member

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    The BC548 was an inverter and can't just be removed without other circuit changes.
     
  8. QAISAR

    QAISAR New Member

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    respected sir i shall be very thankfull to u.now i will make hardware this ckt if any problem find so again i will tell u
    thanks.........................
     
  9. hotwaterwizard

    hotwaterwizard Active Member

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    This one doesn't have it and it works just fine
    [​IMG]
     
  10. sandoelz

    sandoelz New Member

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    Automatic Room Lights

    i have circuits that use SL100, but i can't find this transistor.
    so what can i do. plz help me.:)
     

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  11. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The circuit you attached has a very old SL100 transistor driving a 200 ohm relay coil from a 9V supply. Then its current is only 9V/200 ohms= 45mA. Any little NPN transistor can drive the relay coil.
     
  12. hotwaterwizard

    hotwaterwizard Active Member

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  13. ZaarZ

    ZaarZ New Member

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    Equivalent Sl-100 transistor~

    Dear all,

    I need to design triggering circuit for single phase full wave rectifier. In the circuit, it consist of SL-100.. But, there's no Sl-100 in my simulation software. My ques is, can i change SL-100 to another transistor ? the circuit is look like dis..

    [​IMG]

    Help~
     
  14. audioguru

    audioguru Well-Known Member Most Helpful Member

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    You saved your schematic as a tiny and fuzzy JPG file type instead of as a larger very clear PNG file type.
    So we cannot see the details of the relay that is driven by the old Indian SL100 transistor.

    You must determine the relay coil current and if the base current is enough to turn on a transistor that drives that much current. The 10k base resistor value seems to be too high, but maybe because it is driven from a low current Cmos gate.
     
  15. ZaarZ

    ZaarZ New Member

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    Oops.. sorry, im newbie here...

    Ive attached larger size of the circuits... thanks~

    [​IMG]
     
  16. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The Cmos ICs with a 12V supply will have an output current of 11mA to 22mA if it does not have a current-limiting resistor. But then the output transitor of the IC will get too hot if it directly drives the base of an NPN transistor that has its emitter grounded.

    But the 10k base resistor limits the base current of the transistor to only about 1.2mA so the transaistor's load current can be only 12mA to 24mA.

    The circuit appears to be designed by somebody who knows nothing about transistors.
     
  17. mvs sarma

    mvs sarma Well-Known Member

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    try to use 2N5551 with proper pin out(you need to check). they are generally available in market as used in telephones.
     
  18. ZaarZ

    ZaarZ New Member

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    Thats why i need to re-design this circuit. But, with my current knowledge about this circuit, m not sure whether i can design my own circuit for my project. hope u can advice me... :)

    Yup, i only need a small collector current for the transistor. The current will be used to trigger the gate of the SCR... (just to switch the SCR into ON state).
     
    Last edited: Oct 22, 2009
  19. audioguru

    audioguru Well-Known Member Most Helpful Member

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    No.
    You and I do not know how much current the SL100 transistor provides to the pulse transformer. It might be a lot of current.
    Look at the 51 ohms/2W resistor in series with the pulse transformer. If it dissipates 2W for a moment then its current is 198mA. Then the base current of the transistor needs to be 9.9mA to 19.8mA, not just 1.2mA. Then the value of the 10k base resistor is much too high.
     
  20. ZaarZ

    ZaarZ New Member

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    Maybe ur is right. But isnt the function of that 10k resistor is to limit the base current through the SL-100 therefore it does not burn out the transistor?

    hmm... sorry, but i didnt know much about that circuit designed by book authors.. its just a reference for me in order to construct the triggering circuit. Hm.. Do you have any idea / proposed solution for that circuit ?

    Your help much appreciated~
     
  21. mneary

    mneary New Member

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    If we use the base current to define (limit) the collector current, then the transistor won't turn fully ON. This is worst case for a transistor switch: Current may be 100mA and Vce 6V, a dissipation enough to get it pretty hot. (The reason for 100mA is that the unsaturated gain is more like 50 to 100.) It may sound ironic, but to protect the transistor it must get enough base current to turn fully ON when you want it.

    If you supply 10mA (base resistor about 680R). to the base of a common transistor it'll give you a lot more current even if it isn't technically in saturation. (I can't suggest a transistor because your profile says you are no where.) If Vcc is 12V, the 51 ohm resistor will limit the current to about (11/51) = 215mA anyways, even so that's only if the pulse transformer is allowed to saturate. The oscillator at 4kHz would provide pulses of 12.5 microseconds, so it all depends on the transformer.

    One thing that designers naively do with pulse transformer circuits is to put the diode directly across the transformer primary. This slows down the recovery and severely limits the flyback energy available to the thyristor. (The trade off is that Vce is doubled.when in flybaack. It's 12V*2 or 24V.) Changes shown below.
     

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