Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Buck Converter Modeling

  1. Oct 19, 2014 #1
    Hi I'm currently modeling a 5-12Vdc buck converter, and just out of nowhere decided to put a transistor between the output resistance and the diode. Now, this transistor is always connected to voltage so it shouldn't do anything at all, it's just a closed switch. What happens is that the transistor ends up eating a lot of the voltage. I don't really understand what's happening.

    Circuito.png output.png
    Resistance Voltage. It's 2.... when it should be 12.
  2. jcsd
  3. Oct 19, 2014 #2
    Actually it's a boost. My bad...
  4. Oct 20, 2014 #3
    What is the V at the Emitter of Q2 Relative to the base of Q2?
  5. Oct 20, 2014 #4
    Looks like that a demand for a transistor DC gain (Icollector/Ibase) must be pretty high in this example.
    Check out 2N2222A transistor's characteristics curves.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook