Tech

Build your own resister bank

By Dan Romanchik, KB6NU I’ve written many blog posts about power supplies and electronic loads for AMETEK Programmable Power. This has been interesting to do, and I’ve learned a fair amount about power supplies and electronic loads. So much so, I’d really like to get an electronic load of my own. The only problem is that they’re still a bit out of my price range. A couple of days ago, though, I ran across the article, Versatile Multistep Resistor Load Bank is Simple and Modular in electronic design. It’s a relatively simple design that consists of a number of resistors and switches, as shown in the figure below. R1 – R5 are all the same value, and in this configuration, you can realize 12 different values, from R/4 to 2R. Here’s how you would set the switches to get these resistance values: The right-most column on this chart shows the values you’d realize when R = 1000 Ω. As the author notes, you can cascade load banks to get even more values. You could also build more than one load bank with different resistance values. If you used 100 Ω resistors, the lowest resistance value would be 25 Ω, and with 10 Ω resistors, the lowest value would be 2.5 Ω. This looks like it could be a very useful project to build, and the opportunities to be creative with the packaging are endless.