Just a caveat for anyone using the CPU-heatsink+fan-combo devices from Aliexpress, these things are noisy as FiretrUCK. I knew that they were a bit problematic and was using a resistor+fan bodge instead for PSU noise measurements but didn't realise just how bad they really are until I had to get measurements for something where I didn't have the right resistor values/power levels and pressed this into service. No matter what I did I couldn't get useful readings despite being in an environment set up to minimise noise, until I ran it with a decent-quality low-noise linear power supply. Here's the result at 250mA:
Here it is at 1A:
So they're fine for battery capacity testing, which is what they seem to be aimed at, and fine for checking for voltage stability at various power levels, but no good if you're wanting to make noise measurements at different power levels because most of the noise you'll be seeing will be created by the load.
Now I need to decide whether I want to get a bunch of additional wirewound resistors to measure other voltages at set current levels, or cave in and buy a proper electronic load. I mean, we all know how this is
going to end, but I'd like to at least maintain the pretence that I have options.
Home
Help
Search
Login
Register
