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[SOLVED] Can I replace tantalum capacitor with electrolytic one ?

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eagle1109

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Hi,

I have a training panel for S-300 siemens PLC. The power supply has a broken 24V line. There's a fried tantalum capacitor and there's no similar one in the warehouse.

1706705370421.png


My question is that can I replace this capacitor with 10uF electrolytic one ?
 

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Tantalum capacitors are electrolytic.
There are three commercial types of electrolytic capacitors: aluminum, tantalum, and niobium.

Tantalums are generally more stable and reliable, but you can try replacing is with an aluminum one, and see if everything works okay.
 
Upvote 1 Downvote
How did you burn the tantalum cap?
Are you expecting this condition to happen again?
What was the C, V rating?
What is the lowest DCR load? and freq?
You should never exceed 10% of V rating in reverse and expect it to survive.
 
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Upvote 1 Downvote
There are a lot of advantages of Tantalum over aluminium electrolytic capacitors such as smaller size, higher frequency response, capacitance stability and low ESR etc, however in your application I expect that a aluminium electrolytic will work just fine.
 
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D.A.(Tony)Stewart said:
How did you burn the tantalum cap?
Are you expecting this condition to happen again?
What was the C, V rating?
What is the lowest DCR load? and freq?
You should never exceed 10% of V rating in reverse and expect it to survive.
Click to expand...
pls. answer.
 
Upvote 1 Downvote
With connections through long thin tracks as shown in the photograph, I wouldn't think ESR was considered particularly important in this application. I've had tants blow up for no apparent reason and some when there has been instability on the supply line. Given the circumstances I would expect a normal wet electrolytic to work just as well, if in doubt, wire a 100nF ceramic across it to keep the total impedance lower.

Brian.
 
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Are there electrolytic capacitors within ceramic capacitors values?, I mean is the ceramic capacitor is 10uf?, value important, so where the electrolytic capacitors with ceramic value?
--- Updated ---

eagle1109 said:
Hi,

I have a training panel for S-300 siemens PLC. The power supply has a broken 24V line. There's a fried tantalum capacitor and there's no similar one in the warehouse.

View attachment 188272

My question is that can I replace this capacitor with 10uF electrolytic one ?
Click to expand...
I think you can, as long as same value and voltage
 
Last edited:
Upvote 0 Downvote
The LM2408 is a CRT driver, not a regulator. Do you have the right part number that
24 Vdc is going to ?

ESR major attribute of a bulk cap :

1706795100319.png


Designers, in general choose components and their technology for a reason.

So guessing on substitution can be the difference between " I know for a fact"
versus "I think it might". Also if its handling a lot of switching current can
cause excess heating of cap using one with higher esr......

Other considerations, if this is a life support or safety piece of gear I would take the
safe route.....

Just a thought.


Regards, Dana.
 
Last edited:

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barry said:
This does not explain all, it explains capacitance change over time, and that's it . It does not explain ESR, ESL, tan delta, reverse voltage tolerance, capacitance vs. voltage or temperature, leakage current...
Click to expand...
It explains why we choose Tantalum vs. Electrolytic at a first glance.
 
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BigBoss said:
It explains why we choose Tantalum vs. Electrolytic at a first glance.
Click to expand...
Sorry, but that's totally wrong. You said "this explains ALL". If your only concern is capacitance shift over time, that's a pretty naive approach to picking a capacitor. Of all the characteristics of a capacitor, that's way down on the list of importance.
 

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barry said:
Sorry, but that's totally wrong. You said "this explains ALL". If your only concern is capacitance shift over time, that's a pretty naive approach to picking a capacitor. Of all the characteristics of a capacitor, that's way down on the list of importance.
Click to expand...
You're right..
 
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eagle1109 said:
Hi,

I have a training panel for S-300 siemens PLC. The power supply has a broken 24V line. There's a fried tantalum capacitor and there's no similar one in the warehouse.

View attachment 188272

My question is that can I replace this capacitor with 10uF electrolytic one ?
Click to expand...
ANSWER:

NO

You must choose a low ESR 10 uF Cap, not just ANY 10uF Cap.
Alum. e-caps vary 100:1 range in ESR from std. to low ESR.

And choose > 38V like 50V rating. High V rating is always better.
 
Last edited:
Upvote 0 Downvote
D.A.(Tony)Stewart said:
How did you burn the tantalum cap?
Are you expecting this condition to happen again?
What was the C, V rating?
What is the lowest DCR load? and freq?
You should never exceed 10% of V rating in reverse and expect it to survive.
Click to expand...
The board in the picture is a working board, the second board has a burnt area, and the person who wanted to fix the board didn't know how to fix it correctly and passed the board to me. And I made a mistake and soldered the -ve of the capacitor to the wrong area and it went into flames as soon as I plugged in the mains plug.

So I found it on Aliexpress, it's 10uF 35V tantalum cap.
--- Updated ---

danadakk said:
The LM2408 is a CRT driver, not a regulator. Do you have the right part number that
24 Vdc is going to ?
Click to expand...
I'm sorry it's LM2478 regulator. I wanted to edit the main post, but I couldn't.
--- Updated ---

D.A.(Tony)Stewart said:
ANSWER:

NO

You must choose a low ESR 10 uF Cap, not just ANY 10uF Cap.
Alum. e-caps vary 100:1 range in ESR from std. to low ESR.

And choose > 38V like 50V rating. High V rating is always better.
Click to expand...

Thanks for the answer, I found it on aliexpress 5pcs for like 1$.
--- Updated ---

danadakk said:
Designers, in general choose components and their technology for a reason.
Click to expand...
Absolutely, electronics isn't simple field of engineering just like any other field in life, every thing is selected and confirmed for a reason.

So guessing on substitution can be the difference between " I know for a fact"
versus "I think it might". Also if its handling a lot of switching current can
cause excess heating of cap using one with higher esr......
Click to expand...
I'm sure that I don't know these details about this board. So you're right I should just replace the broken one with the same type.

Other considerations, if this is a life support or safety piece of gear I would take the
safe route.....
Click to expand...
Well, it's a simple 24V linear power supply circuit on a PLC training board.
 
Last edited:

Upvote 0 Downvote
eagle1109 said:
So I found it on Aliexpress, it's 10uF 35V tantalum cap.
--- Updated Today at 3:13 PM ---
I'm sorry it's LM2478 regulator
Click to expand...
Cheap price Quality unknown. ESR should be 2 ohms, if tested, which may be adequate.

You may be dyslexic ...
It's a standard LM7824
 
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