torturing caps

Somebody mixed up some reels, and we got some 0.1uF 16v 0805 ceramic caps in a bin that was supposed to be 50 volt parts.

So, I figured it would be fun to find out what voltage they actually blow up at. I connected 4 in parallel, to a Kepco 3KV power supply.

What I got, scaled per cap, was

400v 5 uA/cap leakage

450 7.5

500 15

540 25

600 50

650 75

700 125

800 200

830 died, about 3 ohms

The current measurements are rough, because at each step the current is creeping down, some sort of DA or something. I let the 700 volt point soak a few minutes, and the current droped almost in half from the value shown.

I won the pool. The Brat bet they would fail at 1500, and Rob bet they would stand the full 3KV. Amateurs.

It would be interesting to measure C vs V. Some other time, maybe.

John

Reply to
John Larkin
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Hi,

Ok, so I could be using cheap 16V/0.1uF ceramic caps on my 100VDC rail, but the only problem is I am guessing the 16V caps capacitance will be far lower than 0.1uF at 100V, compared to an equivalent 100V/0.1uF capacitor. But as you say that would be an interesting test to verify. I had always assumed a 16V ceramic cap could undergo failure if it got a 20V spike on it :)

cheers, Jamie

Reply to
Jamie

snip

Why don't you add a little ripple on top of the DC?

tm

Reply to
tm

At least for ceramic caps, the C/V curve is highly nonlinear and I suspect the voltage rating has some correspondence to that. Viz., The rating really represents the voltage range in which the cap is linear which is generally much less than the maximum breakdown voltage.

Maybe you could do a few C/V curves to see just how much it matters?

Reply to
Stretto

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And yet, you, the "pro" who likes to pretend at understanding physics
and advocates discussing  electronics lets the reason for the drop in
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Reply to
John Fields

Like... who gives a f*** ? ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

What methods do you suggest I could use to investigate it?

Crazy, crabby old hen.

John

Reply to
John Larkin

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I do, and I'm trying to show Larkin up for the fraud he is. 

If you want to help, then do so.
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Reply to
John Fields

Fraud? Do you think I just made up those numbers?

Now girls, try to be civil with one another. You don't have many allies to lose here.

John

Reply to
John Larkin

OK, But it's very boring ;-) ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson
[snip]

I can understand lying about how big your Johnson is, but why would someone exaggerate the volts across a cap?

Bob

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Reply to
BobW

Reply to
Jamie

I have suspected that 1N4001 through maybe 1N4004 all come off the same wafer. 1N4005 through 7, roughly, seem to come off another wafer, behaving a lot more PIN-diodely.

John

Reply to
John Larkin

Well....there are quite a number of usens indie group that would like to know.. ..and would have carried out the experiment, recording data, and presented it out of curiosity and courtesy to all.

Reply to
Robert Baer

On a sunny day (Tue, 14 Jun 2011 19:13:18 -0600) it happened m II wrote in :

Yes I have noticed that I can use some 100 V si diodes up to 600 V without any problem, and that at several kHz on top, same for some bridges,

Reply to
Jan Panteltje

On a sunny day (Tue, 14 Jun 2011 18:53:30 -0700) it happened Jamie wrote in :

I think for things like 1N?00X where X stands for voltage, they just make one diode at say the max voltage, and then print something for the X. Much cheaper than manufacturing different ones for each voltage. So then it is safe to use a 100 V part at 600 V :-)

Reply to
Jan Panteltje

The very old Motorola data almost says that out loud... the recovery times, for example, which are seldom even hinted at on modern data sheets.

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

t

If hypothetically one tested the diodes to see what they were capable of, applying what reverse leakage current level would be good to determine max v ability?

NT

Reply to
Tabby

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