Project: Discrete Master-Slave Flip flop

Discussion in 'The Completed Projects Collection' started by hobbyist, Sep 5, 2008.

  1. hobbyist

    Thread Starter Distinguished Member

    Aug 10, 2008
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    Hi
    This is a circuit I made long time ago and I wrote a paper about it.
     
    Last edited by a moderator: Sep 5, 2008
  2. Wendy

    Moderator

    Mar 24, 2008
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    Interesting... For what grade (college or high school) in school?
     
  3. hobbyist

    Thread Starter Distinguished Member

    Aug 10, 2008
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    No, it wasn't for any homework or anything, it was just for my hobby interests, in learning basic electronic circuits design.
    I took 2 homestudy courses from NRI back some time ago, late 80's early 90's, ,"Basic Electronics" and "Electronics Circuit Design" course.
    But before that,all my learning was, getting one of those 160 in one electronics labs. from radio shack, then building the circuits instructed in the book.
    Then exp. changing components and recording the results until I had some understanding of why it worked the way it did.


    To make a toggle flip flop, on the schematic, I show a dotted line, this is a connection, from the output of the transistor Q8 marked 'Q
    (Not Q) to the transistor Q1 base input marked Data.
    Then toggle the switch marked clock.
    Hope this helps.


     
  4. Wendy

    Moderator

    Mar 24, 2008
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    I notice the article said something about 100ma? I believe you meant 100ua?
     
  5. hobbyist

    Thread Starter Distinguished Member

    Aug 10, 2008
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    Hi Bill

    I just took another ammeter measurement,
    it idles at around 90ma. then when i depress the data switch and clock, it jumps to around 117ma.

    I guess back then when I was just learning about electronics I thought that 100ma. was small, but actually it is alot of current drain especially on a battery.

    I think most of the current drain is through the 470 ohms on the rs flip flops.
     
  6. Venkatesh G.M

    New Member

    Nov 1, 2008
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    sir, i want some guidence for vlsi projects can u help me ?
     
  7. hobbyist

    Thread Starter Distinguished Member

    Aug 10, 2008
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    If VLSI is "very large scale integration" I can't help you there, because I don't know anything about IC's ,my hobby in electronics, Is designing using discrete components.

    However quite some time ago, I did make a very large scale integrated circuit using all transistors and discrete components, it was 2'x2' square, it was a 64 bit ram with a 8x8 led grid, more or less a character generator.

    The ram was made using scr's had to make about 5 power supplies, but all in all it worked really good. I learned a lot about digital logic through that project.

    I think your question would be answered a lot quicker if you posted it in it's own thread in the "projects forum" That way the people can view it more easier to adress your issue.
     
  8. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Hobbyist, I admire your interest in circuit design. I'm a retired EE, and was a circuit designer for my entire career (still am, for that matter).
    Your design is interesting. If you are wondering why the current is so high, you might want to consider that the current through the emitter followers Q2, Q3, Q5, and Q6 (when they are on) is limited only by the beta of the transistors and the base currents through the 100k resistors. This has great potential for smoke.:eek:
     
  9. hobbyist

    Thread Starter Distinguished Member

    Aug 10, 2008
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    Thanks Ron H.
    Thankyou for the complement.
    I see what you are saying, the transistors are probably going into saturation big time. to remedy this I would need to put a base resistor to ground and bias the transistors in the active region enough to get the appropriate output signal, and maybe a resistor in the emitter lead for temp. stabilization, to get rid of some of the Beta dependancy.
     
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