Question Cap on output of PTH reg

[Ewhizz]

Hey guys,
I saw someone advise putting two capacitors on each regulator. Is this a 100uF capacitor for both the input and output?

Thanks

 

[Nold]

Hey guys,
I saw someone advise putting two capacitors on each regulator. Is this a 100uF capacitor for both the input and output?

I always used 100uF & the datasheet has it in the "standard application" schematic, too: http://www.ti.com/lit/ds/symlink/pth08080w.pdf

 

[Ewhizz]

Yes but do I use two 100uf for one reg?
Thanks

 

[Shank]

Yes but do I use two 100uf for one reg?
Thanks

Yes. You don't HAVE to, but you should. It'll clean up the signal a lot which helps prevent other issues

 

[Ewhizz]

Great thanks!

 

[BocuD]

i actually never used caps on the output tbh
I never had issues but its probably better to use them anyways.

 

[Stitches]

i actually never used caps on the output tbh
I never had issues but its probably better to use them anyways.

Oh boy, could Ginger tell you a story

 

[GingerOfOz]

What's this I hear?
It sounds like shrieking.
But from whom?
I must investigate.

Oh the wretched sound!
Emanating from a small box -
A box of mistakes and sorrow
'Tis the Ziploc of broken electronics
Of dead hopes
Of failed dreams

But something is louder
Far far louder than the other boards
A small, black square
A perfect square
A perfect board
Or so it was
'Twould be
A GC+

Perfect no longer
For reasons unknown
But why does it cry?
What makes it moan?

Out from the bag
I carefully withdraw it
And suddenly it says
"YOU'RE SUCH AN IDIOT"

I jump with suprise
This dead board can speak?
"THAT'S RIGHT" the board says,
"DO YOU KNOW YOUR MISTAKE?"

"OUTPUT CAPS"
"OUTPUT CAPS"
"OUTPUT CAPS"
"OUTPUT CAPS"
"YOU LEFT THE REG WITHOUT THEM,
NOW YOU'RE LEFT WITHOUT ME"

"No!" I cry
"This can't be right?"
"The guide just said recommended,"
"Is there another reason that you be dead?"

"NOPE" said the board
"LET'S LOOK AT THE EVIDENCE"
"WHAT ELSE HAS DIED"
"(other than you inside)"

I thought for a moment,
What could be dead?
But then it hit me
And I said with dread:

"The IR LEDs..."
"....On 3.3...."
"....Just like ye"
And the board was silent

No more did it whisper,
No more did it speak,
No more did it yell,
No more did it shriek,

And now, in the silence
I knew my mistake
It all come down
To a voltage spike

Oh, the Wii could take it just fine
Without a whimper or whine
But the LEDs? The GC+?
Those were delicate.

A volatile PTH
And a few saved cents
Result in dead boards
And lots of regret

Here ya go.

To be fair, the output cap didn't fix the mysterious GC+ deaths, but LEDs on 3.3v stopped blowing out. I'd reccomend putting them on your PTHs for sure.

 

[Koksi_90]

Here ya go.

To be fair, the output cap didn't fix the mysterious GC+ deaths, but LEDs on 3.3v stopped blowing out. I'd reccomend putting them on your PTHs for sure.

okay, everything works for me, but what could be broken if I put no caps on the output?
And do i need a cap for all regulators on the output?

Can it be that this error my PIC16F1503 circuit was broken?
There was suddenly no LED more and before it has certainly worked 15 times

 

[MasterNate]

Without a capacitor on the output of the regulator, there could be a small spike in the voltage that could damage sensitive components such as LEDs and the GC+. The capacitor would filter out that voltage spike.

You don't necessarily need a cap on the regulators, it is just much safer for your components if you do. But just put a filter cap on the outputs on all your regulators. It is better that you do.

 

[Ewhizz]

Do you wire both negative pins of the two caps to the middle terminal of the PTH reg?
Thanks

 

[BocuD]

Do you wire both negative pins of the two caps to the middle terminal of the PTH reg?
Thanks

Yea thats probably the best way. Be carefull while soldering tho, you don’t want to heat them up too much. I had caps literally explode on me because i used too much heat while soldering.