Review on 💻 KNACRO 5V 2 Channel 10A PC USB Control Switch Relay Module: Intelligent Driver for Programmable Computer Control by Sean Maile

I just posted the same review for this 5V version of this product except I gave the 5V version five starts and the 24V version three starts because I think that the description of the 24V version of the product should actually be stated more clearly than the 24V version circuit board does not work without an external power supply (but the 5V version does). If I misunderstand the situation please let me know in the comments and I will be happy to update this review and adjust the star rating accordingly. There appear to be nine variations of this product (2, 4, or 8 relays with relays requiring 5, 12, or 24 relays). Volt) and this seller at Revain has it all and I have no complaints about this seller other than the part of the product description I mentioned earlier. I have 2x 5V, 8x 5V and 8x24V. Board, and I believe this review applies to all nine options. ONLY BUY 5-IN BOARDS UNLESS YOU REALLY KNOW WHY YOU WANT TO DO DIFFERENTLY. The voltages on these relays appear to be related to what is needed to drive the electromagnets, not the amount of current. which they are designed to switch (which for all models I assume is 10 amps for your choice of 250VAC or 30VDC). I didn't notice this when I ordered the 24V version to switch the output of some power supplies to 12V DC, but soon found that the 24V version was just lighting up small LEDs to confirm that I'm trying to drive a relay, but the relays don't work. . does not switch, apparently because I have not connected an external 24V DC power supply. I suspect the use case for the 12v and 24v versions might be that you're using a power supply anyway so the relays don't switch when USB power is lost, and maybe a 12v or 24V power supply is cheaper or electrically more efficient. I'm surprised the manufacturer found such cases compelling enough to release such products and not just sell the 5v version, but there might be another reason people are buying the 12v and 24v versions I don't know why you need versions that require a higher voltage external power supply. Finally, a little tip, mostly for Linux users or programmers, although the USB related tip might be helpful for others. . All the boards I bought are controlled by a Linux program called usbrelay, available for Ubuntu ("apt-get install usbrelay"). However, both of my 24V cards seem to have their USB serial numbers set to zero (and I can't easily verify the 2-port card as I write this). The way usbrelay is written there doesn't seem to be an easy way to tell them apart, although it would be possible to recompile this program to source and add such a feature. You can also figure out from source code and internet research how to manage boards by writing command bytes in sysfs files. However, if you want software that only works on Linux, I recommend buying one of these boards that will control all your relays, rather than trying to control multiple smaller boards. This approach also uses fewer USB ports.