Oscillating Volt Regulators?

[Dr.EM]

Interesting reading, didn't know very much about them before. I have installed electros into that project now, so that should be ok (its another mic unit, I may post it up somewhere, its quite neat :lol. I tend to use the highest voltage rating I can that will fit with capacitors.

 

[Nigel Goodwin]

I tend to use the highest voltage rating I can that will fit with capacitors.

With electrolytics the higher voltage the capacitor is, the lower it's ESR is - presumably for size reasons, just like the tantalums?.

 

[chemelec]

With electrolytics the higher voltage the capacitor is, the lower it's ESR is - presumably for size reasons, just like the tantalums?.

Nigel, Ot of Curosity, I tried to Varify this with a bunch of caps I have in my part bins. I tested about 50 of them.
But no conclusive results. Some were lower, others were higher.

The same went for physical sizes differences, between different manufacturers of same value and voltage caps.

Take care......Gary

 

[Nigel Goodwin]

With electrolytics the higher voltage the capacitor is, the lower it's ESR is - presumably for size reasons, just like the tantalums?.

Nigel, Ot of Curosity, I tried to Varify this with a bunch of caps I have in my part bins. I tested about 50 of them.
But no conclusive results. Some were lower, others were higher.

The same went for physical sizes differences, between different manufacturers of same value and voltage caps.

The only ones I've tested have been capacitors from the same manufacturer of the same value but different voltages - and the higher voltage ones have been lower ESR. If you check the datasheets the spec usually shows this as well.

 

[kleberdicas]

I put three LM7805 all of them with capacitors of 1nF and got the frequency of approximately 6MHz !!!

 

[Nigel Goodwin]

I put three LM7805 all of them with capacitors of 1nF and got the frequency of approximately 6MHz !!!

If you look at the thread date, it's over 11 years old!!.

But why would you be surprised when things don't work if you only fitted capacitors a tiny fraction of what's needed?.

 

[kleberdicas]

true friend! but the problem was a friend who rode and did not know why, so I looked for answers on that, and I saw it on your forum ... but thank you!

 

[schmitt trigger]

It's rare to find them used these days, their unreliability caused manufacturers to stop using them.

That plus the blood Tantalum coming from central Africa.

WOW, I fell again into a zombie thread!

 

[crutschow]

The military and NASA satellites I worked on used solid tantalums exclusively for filtering and other high capacitance requirements, where failure is not an option.
Obviously they were high quality, mil-spec devices, used well withing there ratings (typically 50% derating) with strict limits on their inrush currents, etc.