problem with Oscillator and step up transformer

Discussion in 'The Projects Forum' started by badrove, Apr 9, 2008.

  1. badrove

    Thread Starter Member

    Mar 18, 2008
    12
    0
    Hello,

    I use an oscillator scheme to get a sinusoidal wave. i success to get my alternatif signal but when i use a step up transformer with 100Kohms resistor charge instead of my inductance, i get no signal in the secondary coil of my transformer(my transformer features are :Lp=20uH- Ls= 1.05mH )


    do have you some ideas to resolve this problem or can you suggest another circuitry to get an alternatif wave using a dc input(i have to use just transistors and no operationnel amplifier)

    thank you so much
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Post your schematics:
    1) The first portion that works
    2) How you connect in the step-up transformer that causes it to stop working.
    Please include the part numbers you are using for your transistors.
     
  3. badrove

    Thread Starter Member

    Mar 18, 2008
    12
    0
    Thank you for your answer and i don't undestand what do you mean by part numbers. can you explain to me please ?
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The numbers and letters on your transistors, like "2N2222A" or "BC549C" or "TIP121" - something like that. It's usually the uppermost series of characters on the device. They may be very small and difficult to read. Bright light and a magnifier will make reading them much easier.
     
  5. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    There are now a lot of parts soo tiny that you cannot even get the part number off of them :(

    I had these mini-small-outline packages that I had to solder, they only had three alphanumeric characters, which you can only decode from the manufacturer itself.

    Steve
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Do I have a page for you! :D
    http://www.educypedia.be/electronics/datacomponent.htm
    It may take some rooting around, but there are a LOT of resources and links from that site to get precisely that kind of information.

    It came in VERY handy when I was visiting my folks up north - their cordless phone got zapped by lightning, and they REALLY didn't want to try to learn a new model. I opened up the phone, and found that a SMT transistor had the top blown clean off! :eek: After examining all the transistors on the board, they all had the same "1A" character code with the exception of one, that was far away from the destroyed one.

    Discovered via resources on the above link that's the code for an MMBT3904, or a SMT version of a 2N3904. No local suppliers for SMT/SMD's, so I picked up a couple of 2N3904's at the local Radio Shack, soldered one of them in, and they were back in business. ;)

    Two days later, Dad dropped the phone in his bowl of soup :rolleyes: but after another disassembly, cleaning and drying-out, it was back in service - and still working a year later.
     
  7. badrove

    Thread Starter Member

    Mar 18, 2008
    12
    0
    i join my schematic .
    i used a BF245C transistor
    and i always have problem when i insert a transformer instead of my inductance to increase the voltage


    thank you to help me to resolve it
     
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