Voltlog #155 – TL431 0-15V 0-5A Adjustable Power Supply Kit 3AG1 Xiaolin

A while ago I showed this power supply kit, which I ordered from ebay. It was being advertised as an LM317 0-15V 0-5A adjustable power supply kit and it looked promising. Upon receiving the kit and taking a closer look theres 2 thing to mention, one the power supply is not based on the LM317 but on the TL431, they used TL431s instead of op-amps in this power supply design and two there isn’t much documentation about this power supply.

The components used are low quality but that is to be expected from these cheap kits coming from china so no surprises there. If you would like to use some better quality parts I would suggest replacing the electrolytic’s and the TL431s with ones sourced from known sources. Also a nice upgrade would be to use some 10 turn pots instead of the supplied ones to get some finer adjustment. But I just used the originally supplied parts to see what kind of results we get with those.

Get the TL431 power supply from these links:

Here is a screenshot with the signal measured right on the bulk filtering capacitor (4700uF). Looks like this might be the cause of the 100Hz oscillation we we’re seeing on the output.

Here is a screenshot with the current overshoot. The power supply was set for CC 50mA and I suddenly shorted the output through a 1ohm resistor. The scope probe was placed across the resistor leads on the low side ( 1mV = 1mA ). As we can see we have a huge spike of current that could potentially fry an LED connected on this power supply. However the spike lasts less than 1mS which is good and I have observed similar behavior on my HP E3611A analog bench power supply.

Here is also a screenshot with the power supply regulating the current at 50mA in CC mode. This doesn’t look right at all.

Voltlog #119 – NEW 150W Dummy Load Review

Today we are taking a look at yet another electronic load. I found this one on Aliexpress, I think it’s a rather new model so let’s see what it can do.

Here are links to the 150W and the 180W version of this dummy load:

Voltlog #108 – 150W Electronic Load Review

I never expected this electronic dummy load to be so bad because I kinda liked the way it’s built and how it looks. Unfortunately it’s way out of spec on the measurements and also has some firmware bugs.

150W Electronic Load Buying Links:

60W Electronic Load Buying Links:

And here a short user manual that I wrote: PDF 

Voltlog #92 – InTheMail

Welcome to another Voltlog, today we’ll be taking a look at what I’ve been receiving in the mail recently. As much as you guys like watching this stuff, I also like getting all these electronic modules from China. I find it interesting every time I get my hands on a new circuit.

As always I appreciate feedback and discussions in the comments section below, please let me know what you think and don’t forget to like the video, that is always a clear indication of what kind of content you guys like seeing.

Here are links to all the items shown in this video:

Voltlog #82 – DIY Adjustable Analog DC Electronic Load

In this episode I am building an analog adjustable dc load with parts easily obtainable from ebay and banggood. The advantage of such a dc load is that you can understand how it works, modify or repair it if necessary far easier than you would with a digital one. I was able to push mine up to 60W dissipation, but it is recommend to stay under 50W to protect the mosfet.

Here is a list with links to the parts used in this project:

Voltlog #69 – LM317 Kit Assembly Fail

Sometimes, when I have some spare time I like assembling these cheap kits coming from China. Today I am assembling an LM317 adjustable power supply kit complete with voltmeter. Unfortunately they sent me a wrong resistor value so the kit didn’t work as expected but I was able to fix it in the end.

Voltlog #64 – DIY Adjustable Power Supply With Enclosure

Today I’m going to be building a complete DIY analog bench power supply. The actual analog power supply kit (0-30V 0-3A) that I’m going to be using, is this one, it was shown and assembled in voltlog #8. Besides that I’m going to be using this plastic enclosure which I think is quite nice and perfect for such a project, this one can also be found on banggood and there will be links in the description for all the items used in this build.