[SOLVED] Newbie Arduino Pro 3.3V Regulator LD1117 Exploded

[mmk]

Hi All,

Firstly, I would like to thank the originator for this project and everyone that contributed to it. I think this is an awesome home automation DIY and it is so kind of you all to share the knowledge and the knowhow.
Let me introduce myself, I am a Computer Engineer graduate that has been working as a manufacturing Engineer in SE Asia. Technically, I know some electronics but I haven't practice it since my university days. I am more aligned to software programming and computer system. I am so ashamed that my electronic knowledge is so poor and I am determined to learn up proper electronics and I hope by building a project, I can learn better.

So pardon me for my noobish mistake and questionss. I hope you guys can educate me and in some ways my misadventure can be a entertainment to you all .
I want to build a home security system because I don't trust those China made system that is easily available in Ebay. I have big plans for it, maybe one day I fully automate my entire home.

Ok, after waiting close to 1.5 months, I finally got all my parts from Ebay China. I am using a Arduino Pro Mini 3.3V/W5100/RFM69HW configuration.
As for the power supply, I have a AC-DC power supply of 12V-2A barrel output connector. I am using a UTC LD1117A 3.3 (TO-220 package) voltage regulator.

This afternoon while setting up my regulator, I think I screw up badly and my regulator exploded, kaboom. I think I short circuit it somehow.
I wanted to check the output voltage before I hook up an Arduino Pro to it. Previously I burn an Arduino Pro Mini when I supplied a 10V supply into it. So this round, I thought instead of hooking a Arduino, I use a 18K Ohms resistor as a load and hook up a parallel probe (voltage setting) to the resistor to measure the output voltage. I didn't install any coupling capacitors yet. Is it a must and is it why it blew up?

I am using TO-220 package. My pin configuration is pin (1-2-3) as (GND-Out-Vin). Datasheet Link --> UTC LD1117A





Well, it didn't turned out well and the regulator exploded. Part of the regulator body blew up and I was shocked  .
Please do correct me, my understanding is that without the resistor, it would have been a direct short circuit of 3.3V to ground. So, what went wrong? I don't really understand.
I hope my photo can show you how I wired it up and if you guys can't, do let me know. I can do a Fritzing diagram. 

I have a limited LD1117 regulators and I am scared to try again .

[computourist]

Hi mmk , good start !

The only thing I can think of is that you accidently reversed plus an minus, have you checked polarity with a multimeter ?

[papa]

Ouch !!!  Talk about baptism by fire when you trying to get into something.  As it is said, when the magic smoke leaves the electronic part, they do not work very well.

Hang in there.  We all get defective parts sometimes & we all make mistakes sometimes.

The capacitors are maybe not necessary, but helpful. They help smooth out fluctuations in the input & output power. But not having them should not cause your problem.

You are wise to be cautious & check things as you go along so you do not needlessly break things or hurt yourself.

From what I can see of your pictures & description, you seem wired ok. From the LD1117A data sheet, it should be able to handle 12 volt input (up to 18 volts).

Like CompuTourist, I suggest you check your input power with the multimeter, namely is it truly providing 12 volts of power AND is its red wire connected to positive & the black wire to negative?

[mmk]

Hi computourist & papa,

Thank you for replying my call for help. You guys have done a lot of work and sharing the knowledge in this home automation project, my salute goes to you guys (or girls) and if you are guys are in the neighborhood, beers is on me!

papa, I have witness capacitors exploding in the area I worked before and it isn't pleasant. Not to mention, it scares the crap out me. Most of the time, it happens when the polarity is reverse. Yup, mistakes do happened but I can't afford it because buying from Ebay takes a very long time. Local vendor here are expensive and Arduino Pro Mini 3.3V is very rare. I have to tread lightly.

Ok, for now, I will not include the capacitors, less 1 variable from the equation. I am going to put a plastic lid on the regulator next time I am trying the circuit out. Like you said, I could have got hurt from the plastic shrapnel.

I am working right now and I won't be able to check the power connection on the barrel connector but it is likely. I have been reading the UTC LD1117 datasheet again and I think I might have miss-read the pin-out somehow. I can't remember all the marking on the component but the way UTC does their component marking, it is confusing! Refer to the picture below. I remember that I read UTC-LD1117A + "xxxx" and I thought "A" referred to the Pin Code "A" which is (1-2-3) = (G-O-I).

But as I look deeper, I found out that "A" after LD1117 means 1A current output. 



I am going to try again when I get back. As for the calculation part. 
The current going through my load resistor of 18K Ohms :

V = IR
V= 12 V
R = 18000 Ohms

Therefore I is about 0.0006 Amps or about 600 microAmps.
Based on the size of the resistor, I am assuming it is a 1/4 (0.25) watt component.

So, VI = P
V = 12 V
I = 0.0006 Amps

Therefore P = 0.0072 A

So am I right to say that my load resistor should be able to handle the load without burning it self?

I am taking the opportunity to practice what I learn so that I can remember better. I am hoping that by doing so, any newbie that reads my post will be able to learn as well. I am so excited working on this home automation project as I feel that this has so much potential. Working together, we can bring it the next level. But first, I need to stop breaking my components. 

[mmk]

Updates

Power supply barrel connector cable connected correctly. I took a macro shot at all 3 UTC LD1117 regulatos and they all had the same marking. I am trying to match the markings to what is in the datasheet but I can't seems to be able to figure it out. What do you guys think?

UTC LD117A 33D_HASD0W

Is it an imitation regulator?

[papa]

OK, I finally found this data sheet for a UTC LD1117A  It seems to use a coding system better matched to your chip, maybe older?  They do have in common the same pin assignments for a pin code D.

According to my reading of the data sheet I found for a TO-220 package & a code of LD1117A 33D... means 1 amp current, 3.3 volts, pin code D (left to right facing front: in, gnd, out) PLEASE CHECK MY READING OF THE DATASHEET I found.

Translating that code reading to what I can see of your pic, that would mean you wired circuit gnd to voltage regulator input, circuit output to voltage regulator gnd, & circuit input to voltage regulator output. If I'm correctly reading the right data sheet & your pics, then this could be your problem.

In my opinion, responsible vendors post a link to the right data sheet for what they sell.

By the way, another way to do this project is to build it with Buono Uno Arduino clones that can switch between 3.3 volts & 5 volts.  See my Success... posts for schematics & examples.  For me, they work well with CompuTourist's Gateway & node Arduino sketches.  Maybe the Buonos would be easier for you to obtain than Pro Minis.  I've bought 5 of these Buonos at a time here, but they also sell one at a time.  Unless one taps the current a great deal, the Buonos (unlike the ProMinis) do not need the extra circuit with the voltage regulator to supply enough current.  Again see my version of the schematics that do not include that circuit.

I hope some of this helps.

[mmk]

Hi papa,

I can't seems to access the datasheet you provided. Can you confirm the link?

[Edit] 

I found it on Google. I am reading it now.
I got it. You are right, I hooked it up to the wrong pins. Should be "D" pin configurations. For those that are interested, below picture is a snippet from the datasheet and what is on my regulator marking.

Thank you very much, papa!

[papa]

You're welcome. You can help someone else sometime, maybe me.

PS  Where I can, I like to use ceramic capacitors so I need not deal with polarity & they take up less space than a polarized capacitor.

PPS I fixed the link to the matching data sheet for the voltage regulator.

[mmk]

To papa, noted on the capacitor choice.

Finally! Step 1/100 accomplished. It didn't explode, perfect 3.3V! Muahahaha.

[papa]

Good news! I hope the rest of the project goes well.