EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: matthuszagh on February 11, 2024, 02:22:13 am
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I'm building a really simple resistive load for power supply noise measurements. One of my requirements is that all connections between power supply, load, and measuring device be shielded to avoid noise pickup. My plan was to fasten a wirewound resistor to the inside of a diecast enclosure and use a panel-mount SMA connector for the power supply and measuring device connections (I was going to use an SMA tee to allow connections to both). Because I'm not too worried about adding inductance to the load (it's already a wirewound resistor after all), I was going to solder one side of the resistor to a solder lug lock washer (something like https://www.digikey.com/en/products/detail/keystone-electronics/7316/316689 (https://www.digikey.com/en/products/detail/keystone-electronics/7316/316689) but of the appropriate hole diameter). The other side, of course, would solder to the SMA center pin.
However, my searches haven't turned up much, except for this: https://www.aliexpress.us/item/3256803753366565.html (https://www.aliexpress.us/item/3256803753366565.html). I don't really want to wait that long for something though.
I don't really want to deal with coaxial cable on the inside. The pig tail would be pretty long to reach both ends of the resistor, and it just seems unnecessary.
Another option is I could try to solder a wire to the inside of the enclosure right next to the coaxial connector, but IIRC people have told me soldering to aluminum isn't easy.
Or, I could just wrap wire around the threaded portion of the SMA connector on the inside of the enclosure and just fasten a nut on top of it, but that seems like it could come out.
Anyone know of something I could use? Or, is there a better way to do this?
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Something like this?
(https://mm.digikey.com/Volume0/opasdata/d220001/medias/images/595/33458.JPG)
The SMA jack washer has an inside diameter of 0.262" (or 6.65mm), so a ring terminal for a 1/4" stud should fit.
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just drill some crap out
you can literary take a piece of copper sheet, drill a hole in it by sandwiching it between two pieces of wood and solder to it. you can even file the edges off to make it a more palatable shape that is if you don't have a lug you can enlarge. you can even get lower inductance if you drill out a strip and route it to where it needs to be then using a wire, just throw some heat shrink over it. the only trick is to have a sharp drill bit because a old ass worn out one will mangle the hole in thin material
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You don’t need the solder lug and lock washer to be the same item. You can just use a lock washer and a separate lug. Mount them so the lock washer is between the case and the lug, so its teeth bite into both.