1. We will be in Read Only mode (no new threads, replies, registration) starting at 9:00 EDT for a number of hours as we migrate the forums to upgraded software.

year 2 project: programable load

Discussion in 'General Electronics Chat' started by bug13, Mar 19, 2013.

  1. bug13

    Thread Starter Senior Member

    Feb 13, 2012
    Hi guys

    I am thinking to built a programmable load as my year two project, just want to know what you guys think before I do anything silly, in terms of complexity and other stuff that I don't know, and whatever I need to know.

    Design goal:

    • Constant current/5A max/1mA minimum resolution (realistic?)
    • Constant resistance (I have no idea what a realistic spec for this one)
    • Constant power/60W max (not a fix requirement, I am into low power stuff, make sense?)
    • reliable/necessary protection etc
    • reasonable accurate
    I am hoping to have a working prototype by July. (components selection/design, PCB, software etc). Cost of material within $100.

    Advice/suggestions? feel free to say anything :)

    PS: my year one project (with flaws)
    Last edited: Mar 19, 2013
  2. BillB3857

    AAC Fanatic!

    Feb 28, 2009
    You may want to add some modulation to the load as well. It can be used to check for power supplies that can't keep up with a rapid change in load. We have an old boat anchor type at work that has variable frequency, variable duty cycle, variable percentage of full load modulation.
  3. bug13

    Thread Starter Senior Member

    Feb 13, 2012
    So I assume that can be easily implement in software? depending on the speed of the DAC?

    If this add too much of a complexity, I would prefer to keep it simple :), it's very nice to have some modulation tho, as I am into digital stuff.
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Sorry I missed your previous project... well, I missed it this time too as I didn't click the links. But overall it looks good.

    A good load is a joyful thing. I got to use one long ago when setting up a test stand for some voltage regulators. 4th attempt at the fixture and the one that actually worked well as I was smart enough not to get too smart.

    Constant current, voltage, and resistance should be there. A step modulation should also be included, if in just the current mode.

    Voltage and current measure and reporting also good.

    Can you make it sit on the end of a USB cable?

    I would use this as a starting point for your design spec.
  5. bug13

    Thread Starter Senior Member

    Feb 13, 2012
    haha it's all right, you have always been great help to me :)

    What's the constant voltage for anyway? I don't think of a way for it to be useful.

    USB cable sound nice.