Current/Load

Discussion in 'General Electronics Chat' started by ShockBoy, Aug 14, 2010.

  1. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
    186
    0
    On my simulation program, Yenka, I've got your average two npn transistor led flashing circuit. Works great, I then add a transformer and get from a 10:85 ratio about 80 volts ac. Starting voltage is 12v.

    I understand that stepping up the voltage reduces the current, but I can't even put an ammeter on the simulation, it blows up the components. I've successfully achieved 80vac but what to do with it? Any suggestions or info would be great because I'm at a loss.
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    We will need a schematic to make any progress with your question.

    hgmjr
     
  3. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
    186
    0
    This is just a screen shot, both led's blink and the voltage at the top alternates from 79.3 to -79.3v
     
  4. kkazem

    Active Member

    Jul 23, 2009
    160
    26
    What do you mean "but what to do with it?"

    That should be your starting point, not something that pops up in your head after making it. What do you want to do with it? I suppose since your name is ShockBoy, perhaps a circuit that shocks people as a gag may be in order. Actually, I'm only kidding. If you don't kn ow what you're doing, and I mean both from an electrical engineering and a physiological point of view, don't try to make a shocker circuit as you could hurt someone or yourself. And it's not just the voltage, but the pulse time as well.

    Anyway, before us engineers start a design, we have specs that tell us what to do. IF it's for ourselves, we write the specs, but we never just start hooking things up and then ask--what do I do with this? The only exception is if you're doing pure research, and even then, you would have a goal in mind prior to starting.

    Good luck.

    Regards,
    Kamran Kazem
    V.P. & CTO
    Magnetic Design Labs, Inc.
    I.E.E.E. Senior Member
     
  5. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    An ammeter tied across your output will act as a dead short. No wonder it "blows things up. You need to put a current limiting resistor in series with your ammeter. Start with a 10K and see what happens.

    After looking at your circuit, I can see the output current available should be a little less than 2 ma. Your input current to the transformer is limited by the 470 ohm resistors. You already mentioned you understand how the current available is reduced when the voltage is raised by the transformer.
     
    Last edited: Aug 14, 2010
  6. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
    186
    0
    Thanks kkazem. I'm a complete amateur and I never intended this to be a shocker, I was leaning more towards the pulse/frequency aspect of it. Being a led flasher I am interested in the inverter aspect of the pulses. Another possible use might be a use with my solar panels. Longer capable distances if the dc was, 1 for 1, converted to ac directly at the panels. Either way, current is my issue.

    When I said what to do with it, I was thinking more along the lines of measuring the current at the up side of the transformer, but I am uncertain how to do that. In the program, I hook up the ammeter to the leads and it quickly drains the circuit and/or blows components.
     
  7. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
    186
    0
    Thanks Bill, I will try the 10k resistor in series.


    Edit: It still drained the circuit.
     
    Last edited: Aug 14, 2010
  8. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
    186
    0
    I figured out why it was shorting out, Duh:rolleyes:

    I needed to ground the ammeter off of one of the transformers out pins. Its reading 8.32uA and the voltage has changed from 84.0 to 83.7v
     
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