5.1V 3A Power Supply Compatible with Raspberry Pi 4 ON/Off Switch, USB-C Pi 4 Charger Raspi 4B Adapter for Raspberry Pi 4 Model B 1GB 2GB 4GB 8GB Version

I have confirmed this does work with a raspberry pi 3B with the included micro-USB adapter. There is no low voltage warning and the switch is not a bad addition.

I needed a Raspberry Pi 4-compatible charging adapter (5.1V 3A specifically) to charge my GRS Build-A-Cade. None of my USB-C chargers or high-output battery banks (ones I use for my Switch and Steam Deck) worked at all (no power light by the power port when plugged in). Thankfully, the BAC manual mentioned AC adapters of this specific type, so I placed my order immediately.I was so relieved to see the charging light on the back of my BAG immediately light up red (low battery/charging indicator)! I'm waiting for the unit to fully charge, but I can already tell it's going to work out well in the long run.The built-in power on/off switch on the cable is great to have for hard RPi shutdowns (instead of shutting down then unplugging the cable out every time).Figured I'd mention the specific use case in my review headline in the chance it helps others who are in my same situation. This is the one to get, y'all!

This Smraza power supply is a great choice for your Raspberry Pi 4. The included on/off switch is super handy for easy power control. It's delivered consistent power to my Pi without any issues. Plus, the build quality feels solid. Definitely recommend!

I’ve tried many power supplies, some seem to work ok for awhile but usually end up with low power warnings and screen flashing.So far, this one is working great. I really wish, however, that the on/off switch was a rocker or had visual indicators for its state.

I have a number of really nice 5V AC adapters, unfortunately the Raspberry Pi expects slightly higher voltage to not complain. While these appear to be inferior to my other supplies, running at about 5.15V with no load keeps the RPi from popping up the voltage warnings.

This fixed my low voltage warning in octoprint!

I've tested a half dozen types of such wall wart designs for Raspberry Pi 4/400 uses and I've standardized on this brand for my last 8 applications. Why? Because after testing with an electronic load at various currents from 0.25A to 3.0A this brand has consistently shown the best voltage regulation. (Some other brands will drop down to 4.7V at high loads, which I consider unacceptable.)As to the complaints of some reviewers, first, I've never run across a low-voltage Pi error using these power supplies. It's certainly possible to run into the occasional lemon, especially for a $10 piece of electronics. There's a reason I test every power supply before connecting it to my equipment after all. But as alluded to above, after 8 tested units I've never found the Smraza-branded Intertek designs to vary by more than 0.1V over the entire range of possible current loads.As to the RF/EMI issue, wall warts typically use switching supply ICs and hence you're virtually guaranteed to run into some emissions. If you have audio or radio environments where that's a problem you can either clip a couple of ferrite core suppressors along the antenna's, er, power cord's length or cross your fingers and hope that the $15 official Raspberry Pi power supply will do the trick.

In run a Pi3B+ and a Pi4 for ham radio applications. No more low voltage lights/warnings and the added adapter is very useful.