electrolytic caps VS. tantalum caps

[tvtech]

Tantalums have their place and application. They are very good at certain things. And fail miserably at others.

Ripple current = FAIL.

Timing circuits = WIN. Like most things in Electronics....live and learn. I have yet to have a Tant die on me in a timing circuit.

Different horses for courses. Of course.

Have fun guys

TV Tech

 

[bountyhunter]

Just checked six different TV's, from a brand new LCD one to one 12 years old - can't see a single tantalum capacitor in any of them. In fact I've not seen any since the late 70's early 80's when they were dropped because of their poor reliability.

Tantalums are not unreliable if properly used. However: their ESR (series resistance) is so low that they have large inrush surge currents if the current is not limited by some means. That can cause them to fail. We used solid tantalums in many military products because their ESR remains low over the full temp range while aluminum electrolytics have ESR go straight up at temps below about 10C. You have to know what you're doing to design with solid Tantalums, but they are good for specific applications.

One place they are used a lot is in "support" around the CPU socket on a mother board. We also used them a lot on the output of switcher converters, but we used Tantalums designed for high frequency switching (low ESR, high resonant frequency type)

 

[tvtech]

Tantalums are not unreliable if properly used. However: their ESR (series resistance) is so low that they have large inrush surge currents if the current is not limited by some means. That can cause them to fail. We used solid tantalums in many military products because their ESR remains low over the full temp range while aluminum electrolytics have ESR go straight up at temps below about 10C. You have to know what you're doing to design with solid Tantalums, but they are good for specific applications.

One place they are used a lot is in "support" around the CPU socket on a mother board. We also used them a lot on the output of switcher converters, but we used Tantalums designed for high frequency switching (low ESR, high resonant frequency type)

Amen and thank you. Correctly used, Tants are good to go.

Tv Tech.

 

[rogerazsmith]

Tantalums versus electrolytic caps

Hi All

Thanks for your input, thought it might be a dead thread- no so.

The failure occured in a Yaesu high power PA. The manufacturers fitted the 16v device onto the push pull o/p base bias. Here are big currents so maybe the ripple is the problem. I have replaced like with like and will give it some stick and see if it goes again.

If it does I will try and get higher voltage or try one of the Low ESR electrolytics I have and see what happens.

BY the way tantalums don't spray aluminium all over the place, but the stink awful. My radio shack smell dreadful.

regards to all

Roger

 

[rogerazsmith]

tantalums vs electrolytics

Further to my last post:

Correction the cap in question is on the driver transistor pair supply rail, not bias as stated earlier!

The new device fitted like for like, also had thermo couple attached. When an unmodulated signal driving at full power device was unaffected. When modulated signal applied and full power temperature rose to 70C in about a minute and would have destucted shortly after. So it is the audio component; the ripple current which is the issue.

I changed the 10u 16vdc cap for a 47u 63v electrolytic (three times as big!) Temperature rise about 10 degrees max after 5 minutes at full modulated power.

So now the jobs a good 'un as we say in South Yorkshire! Both types have their place!

Thanks everybody for your input.

Regards

Rogerazsmith

 

[tvtech]

A last word for this thread...

Tantalum Caps are hugely misunderstood. That's why they have such a crappy "reputation".

They are actually beauties if used in applications they were designed for.

Thanks,
TV Tech

 

[chemelec]

A last word for this thread...

Tantalum Caps are hugely misunderstood. That's why they have such a crappy "reputation".

They are actually beauties if used in applications they were designed for.

Thanks,
TV Tech

I Totally Agree

 

[dwonda]

Ok I have a question for all of you since you guys seem to be pretty knowledgeable about this stuff. I recently had to do a minor electronic repair on my climate control unit for my car, and I followed this tutorial, https://www.pelicanparts.com/BMW/techarticles/Borrowed/E36-Climate-Control-Repair.htm however I couldn't find the right tantalum capacitor so I used an aluminum electrolytic .47uf 50v. From what I understand this capacitor functions as a filter. Which kind of capacitor do you think would have been choice in this application?

 

[chemelec]

Is it now working OK?

If So, than don't worry about it.

I have the 0.47 Tantalums.
And if Needed, I could send you a couple of them for Free.

Gary

 

[dwonda]

Ya its working ok, thank you so much for your offer, but please don't go through that effort on my account. I was just curious to know for the sake of argument which would have been better in this application.

 

[chemelec]

Well the Tantalums are Probably Better or they would not have used them.
But without seeing the Schematic it dificult to know for sure.

Gary