Author Topic: What shall i replace this Capacitor with ?  (Read 571 times)

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Offline Retromat

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What shall i replace this Capacitor with ?
« on: November 20, 2020, 01:55:13 pm »
Greetings!

today i wanted to get a old [attach=1]ISA Graphicscard to work and noticed a broken off, in my opinion, tantal capacitor.
The values say its a 10uf Capacitor. Is that correct? I do not own those types of capacitors but i have some ceramic capacitors laying around and wonder if i could replace it with them.
also, does 10uF doesnt sound a lil too high for this lil fella?
 

Offline pigrew

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Re: What shall i replace this Capacitor with ?
« Reply #1 on: November 20, 2020, 02:04:04 pm »
It's a 10uF 16V tantalum capacitor. Without a circuit schematic, it's unclear if a ceramic capacitor would be an acceptable substitute.

Be careful with orientation, they'll catch fire if you reverse the polarity.
 

Offline Infrared_Fred

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Re: What shall i replace this Capacitor with ?
« Reply #2 on: November 20, 2020, 03:16:33 pm »
That capacitor looks to be the correct size for its value and voltage range, i.e. I don't think it is broken off.  A capacitor like this https://www.digikey.com/en/products/detail/avx-corporation/TAP106K016CRW/3661004 matches the apparent size of your capacitor. 
 

Offline Retromat

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Re: What shall i replace this Capacitor with ?
« Reply #3 on: November 20, 2020, 03:19:14 pm »
thanks!

yes i took a picture of a unbroken one for easier reference. Hmmm os i better get a new tantal one the nand do not replace it with anything else.
 

Offline David Hess

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Re: What shall i replace this Capacitor with ?
« Reply #4 on: November 20, 2020, 06:38:31 pm »
You could replace it with a 47 to 100 microfarad aluminum electrolytic.
 

Offline uli12us

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Re: What shall i replace this Capacitor with ?
« Reply #5 on: November 21, 2020, 10:19:47 am »
No, replacing with a standard Electrolytic is nearly always ok, but the capacity must be the same, the voltage can be higher.
 

Offline David Hess

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Re: What shall i replace this Capacitor with ?
« Reply #6 on: November 21, 2020, 11:17:05 pm »
No, replacing with a standard Electrolytic is nearly always ok, but the capacity must be the same, the voltage can be higher.

That depends on the application.  If decoupling applications it is the ESR and impedance which matter and not the capacitance, in which case it takes an aluminum electrolytic of 4 to 10 times the capacitance to yield the same performance.
 

Offline james_s

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Re: What shall i replace this Capacitor with ?
« Reply #7 on: November 22, 2020, 04:32:28 am »
I've measured the ESR of a few different tantalum capacitors and while it was lower than a typical cheap electrolytic it was not THAT low. I would be quite surprised if a reasonable quality aluminum electrolytic of the same value didn't work.
 

Offline tggzzz

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Re: What shall i replace this Capacitor with ?
« Reply #8 on: November 22, 2020, 10:06:29 am »
In some circuits a capacitor with a lower ESR can cause problems. I guess that isn't the case in your circuit.

If using a tanatalum, ensure the rated voltage is at least twice the voltage in the circuit. A 16V tant would be fine for 5V, but 12V would be questionable.

With MLCC capacitors, the capacitance is strongly dependent on the applied voltage. It is normal to "lose"  80%-90% of the capacitance when running them at their rated voltage.

David Hess' suggestion is sensible for a standard alumimium electrolytic. Some of the new modern polymer electrolytics have a surprisingly low ESR.
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Offline mariush

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Re: What shall i replace this Capacitor with ?
« Reply #9 on: November 22, 2020, 12:24:26 pm »
I'd use a 10uF 35-50v rated electrolytic capacitor. 

A 10uF 16-25v electrolytic would probably have a bit too high esr compared to that of the tantalum capacitor (which i assume it would be somewhere around 0.15-0.3 ohm esr)

 

Offline james_s

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Re: What shall i replace this Capacitor with ?
« Reply #10 on: November 22, 2020, 05:28:56 pm »
I'd use a 10uF 35-50v rated electrolytic capacitor. 

A 10uF 16-25v electrolytic would probably have a bit too high esr compared to that of the tantalum capacitor (which i assume it would be somewhere around 0.15-0.3 ohm esr)

My experience has been that electrolytics with a higher voltage rating have higher ESR, all else being equal. Those with the smallest physical size also typically have higher ESR.
 

Offline David Hess

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Re: What shall i replace this Capacitor with ?
« Reply #11 on: November 22, 2020, 05:32:40 pm »
I've measured the ESR of a few different tantalum capacitors and while it was lower than a typical cheap electrolytic it was not THAT low. I would be quite surprised if a reasonable quality aluminum electrolytic of the same value didn't work.

The high frequency performance of solid tantalum capacitors is better than that of aluminum electrolytics which a common ESR test will not reveal, so it takes a larger value of capacitance to get a similar impedance at higher frequencies.  This is reflected in application notes for regulators where the suggested output capacitor will be either like a 1 microfarad tantalum or a 10 microfarad aluminum electrolytic:

https://www.ti.com/lit/ds/snvs778e/snvs778e.pdf?ts=1606066065524&ref_url=https%253A%252F%252Fwww.google.com%252F
https://www.ti.com/lit/ds/snosbq7c/snosbq7c.pdf?ts=1605982101539&ref_url=https%253A%252F%252Fwww.google.com%252F
 


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