YwRobot Breadboard power supply passing voltage problem

I use a yw power supply(YwRobot Breadboard Power Supply) for a year and now i have big problem with this module, when i checked out output voltage on 3.3V pin and its shown 3.3v and on 5 v pin the multimeter shown 12 volts!!!(my adaptor output voltage).

Is this board not suppose to protect output from over 5v and 3.3v ?

Whats happening ?!?!?! why this board act like this !??!

Ouch! Sounds like your 5V regulator is shorted. I’ve burned many of these out. The regulator can be replaced. Look for AMS1117-5.0 or get another one. Don’t use it until fixed.

Sh..!! :confused:

How to protect my other parts from over voltage like this?
In the datasheet of ams1117 noted that ams1117 does not need protection, why this one pass all voltage ?!

They are not indestructible. They usually burn out because reverse voltage gets applied to them. They have some current limiting but on a short on the output could burn it out. They are pretty good for being so small but like anything you can let the magic smoke out.

Thanks man,
Is there any way that i can protect my other parts from over voltage always ? if there is situation like this happened again ...

OK, now the problem with this module is the same as the various Arduino modules using a tiny regulator on board, they are just capable of powering the ATmega chip itself and a few other things, but attempting to power anything else requiring significant current - over 100 mA - is not going to end well, especially if fed with 12 V.

This module is best operated by plugging a 5 V regulated "phone charger" into the reverse USB jack on the board.

I have to chuckle at this quite from the page you cite:
"When you receive your board, it is a good idea to check the output voltage levels with a digital meter to make sure that it is operating correctly and providing the correct voltage levels. You should get exactly 3.3 V and 5 V at the outputs.You should also thoroughly check your breadboard project circuit, and double check all the voltages before you connect it to anything else."

The supply is simple, just the minimum components needed to give you an easy way lay down 5/3.3v for breadboarding (prototyping and testing) not recommended for any high current or permanent use. Just understand that and use it cautiously as Paul outlined. They’re handy to have around. I paid about $1 each and have one for every breadboard I have. It’s cheap convenience. I also have 3 different lab supplies but this is easier in many cases and all I need. It’s possible to design a shunt circuit to cut off if not working but it starts to get bigger and cost more. Every time someone has a great idea it adds to component count, complexity and ultimately cost.

Hi guys,
Thanks for all your answers,
So if this module is for test with highly precaution, what is best solution for using in the project with 3.3 and 5 v output ?

I read some articles and more of them talk about linear regulator like ams1117 or lmxx it others.
And some of them tell to use buck convertors.
Which one is better for long use with out fearing of something bad happen?(my 5v relay module fired)

And one other thing, after 5v problem 3.3 v pass all input voltage too so I buy multiple new ams1117 and replace them with old ones on ywrobot, and everything fine for a while, but after that, 5v output starting to pass all input voltage! Again! Why???
I make another PCB with extra ams and capacitors(100uf25v, 10uf16v) that I have, 3.3 v works fine so far, but 5v on this board start to pass all input voltage !! :(((

Why ?? What’s the problem?? Are these ams parts so easy to break? Or I did something bad and wrong ??

Reread #5 only about 100 mA safely when powered by 12V.

Why ?? What's the problem?? Are these ams parts so easy to break?


It's no contest.

Go and buy a number of the switchmode "buck" converters available on eBay and Aliexpress.

Get ones that either have a fixed output voltage, or a decent looking potentiometer to set the voltage, like this one:

Not a scrawny little potentiometer like this:

I mean, the little one might work just fine, but it does not look trustworthy.

These are rated for up to 28 V input so should be reasonably safe to use from a car battery if necessary. They may not be short-circuit proof however.

I can confirm they are not short protected, but if used carefully including doing your load calculations you should be fine.

Thanks wolframore and Paul_b for your support and complete answers,
I have a prototype pcb on breadboard with one pcf8574 and one esp01 and one dual relay module and one pir hc-sr501, i think ams1117 can't supply all current that is need for this collection. i think adding pcf8574 break down ams because before that everything works fine with this ywrobot .

Can i use some kind of these buck converters with 3A output for all of these ??

Yes... the AMS1117 is designed for about 0.2A in the best case

Even if the switch converters are rated higher than they should be, I'm sure they would be good for at least 1A.

Yes... the AMS1117 is designed for about 0.2A in the best case

Even if the switch converters are rated higher than they should be, I'm sure they would be good for at least 1A.

Then ams is not right choice for my project?
Buck convertor is good or not ?

Reread #5 only about 100 mA safely when powered by 12V.

If i read right datasheet of ams1117, it said if (vin-vout=1.5v) output current would be between 900 to 1500 mA, is that right ?
If I put 6v input on ams1117-5v with 1.5A current, it would be work fine to 5v with 1.5A current max output?

try it... there's a lot more information in the datasheet, if you think you can achieve it you should try it. You have to consider all the specifications in a datasheet not just one thing that supports what you want. It will fail as you described.

Vin- Vout = 1.5V
Then Vin = 1.5V + Vout
6.5V = 1.5V + 5V

So no, 6V won't do it.

1.5 amp will require good heatsinking as the part will be dissipating P = I x V, 1.5A x 1.5V = 2.25W of heat.

It’s about 90C per watt in really well ventilated large copper pour.. it’s just not gonna happen