I ordered a bunch of SMD diodes from AliExpress (nine different types), and nine packages arrived, but they weren’t labeled. I tested everything to infer what I got, and they didn’t ship me what I ordered. My notes are here and the video of me doing all this is here.
I kept a note of the seller and will try to not order from them again. In the mean time I think I have filed the components that did arrive in the correct drawer.
Below are two happy snaps from this project. I guess on the bright side I got some practice doing SMD soldering and using my signal generator and my scope.
Oh, and I added a new item to my debugging notes, viz “is it plugged into the right socket?” (I had my output cable on the signal generator plugged into the wrong BNC connector on the device, that took some figuring out…)
I had an envelope full of SMD diodes arrive today. Three different types in three different sizes, so nine bundles. Unlabeled!
I’m not sure what they were thinking at the shop. I got them from here.
I managed to figure out that the ones marked ‘S4’ were the Schottky diodes (1N5819WS). I think the ones labeled ‘T4’ are the switching diodes (1N4148WS) and the ones labeled ‘T7’ and ‘A7’ are the rectifying diodes (1N4007), but I’m not sure of that yet.
The reason I had trouble configuring this electronic load is that I thought the “cutoff voltage” was a maximum setting, but in fact it means cutoff if the voltage drops below this value. That makes sense of course, especially as the main use case for this device is testing batteries. Once the voltage drops below a certain level the battery is dead and you can stop testing.
The trick with the wiring is that you can just hook the voltage and current terminals up to the battery / power supply terminals. I think the idea is that you can put the voltage and current terminals in different parts of a circuit, but I don’t really understand that, and for simple battery or power supply testing it seems you can just connect them together.
There are two modes available: Constant Current (CC) and Constant Power (CP). I have managed to get the software working and connected so that should mean I can put this up the back of my bench and control it remotely, which will be handy.
My next video will be me making a cable to fix this mess. Once I have that cable I will make a video demoing the EBD-A20H.
In this video I use a 100W 6Ω resistor to test my Riden RD6006 power supply at various voltages from 1V to 18V up to a maximum power of 54W.
I should note that in this video I tried to draw 54W of power from the power supply, but the power supply is only rated up to 45W so I probably shouldn’t have done that, and won’t have any reason to ever do that again, I was just testing the maximum. So maybe don’t do that at home. :)