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Old 05-01-2019, 07:29 AM   #1
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Default Smd capacitor

Hi badcaps,


Do smd capacitors go opened or shorted only
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Old 05-01-2019, 09:01 AM   #2
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Default Re: Smd capacitor

it depends on the type,
ceramics can short, others just change value.
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Old 05-01-2019, 12:03 PM   #3
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Default Re: Smd capacitor

Ok But what about those without any reading infact i tested a pair without reading
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Old 05-01-2019, 01:20 PM   #4
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Default Re: Smd capacitor

Just to confirm, when you checked the cap, what were you measuring? Was it with continuity mode? If so, then it appearing "open" is normal. If it was for capacitance and it isn't a decent meter, then you may just be measuring something too low a value for your meter to handle (say pf values). Additionally, capacitance in circuit is pretty sketchy.

Do you have a signal generator and oscilloscope or an LRC meter? If so what LCR meter do you have?
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Old 05-01-2019, 01:25 PM   #5
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Default Re: Smd capacitor

I was using a FLUKE 179 and i tested it in the diode mode.

No i have neither of the 2 equipment just yet.

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Old 05-01-2019, 04:03 PM   #6
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Default Re: Smd capacitor

a capacitor only passes AC, diode mode uses DC and reports the voltage-drop.

that's why it's called "diode mode"
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Old 05-01-2019, 04:51 PM   #7
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Default Re: Smd capacitor

Ah, that's what I was wondering on the "Open" bit. A better way to test the capacitor with the meter Gear sir, would be to take the capacitor out of circuit, then put the meter into "ohms". What you should see on the capacitor is that the ohms reading should start lower and rapidly count up, until it eventually says "OL" for overload. This is what a good capacitor does. After that, you would short the cap out to discharge it, then try it again in the other direction. A note on this though.. If you are measuring something in the pico farad's range, it may charge too to quickly to observe any ohms measurement at all. In reality though, unless you are reading a short on a power rail and have eliminated the more likely causes of trouble, it probably isn't going to be one of the ceramic capacitors. It could be a tantulum or electrolytic, but ceramic capacitors just don't fail often and really don't fail open often. For one to fail open would be kind of like like winning the lottery. (only in a bad way. lol)

But yes, what STJ said about Capacitors not passing DC, only AC. Additionally, testing anything capacitor related without taking the capacitor out of circuit is basically not accurate. The most accurate in circuit test is generally an ESR test and you won't be able to do that easily/at all with only a multimeter.

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Old 05-02-2019, 02:37 AM   #8
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Default Re: Smd capacitor

I believe i am talking about SMD ceremic capacitors. ok then thanks Retro i believe I'll have to do my math. will try harder
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Old 05-02-2019, 08:35 AM   #9
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Default Re: Smd capacitor

Oh, no worries! Capacitor testing is always one of those things that throws people when they first start doing it. It is deceptively complicated, at least in comparison to most of the other parts that you use.

Something you may look at getting that would probably help starting off is one of these little component tester devices.
KKmoon MRH1631426738275XW Multifunctional LCD GM328 Transistor Tester Diode Capacitance ESR Voltage Frequency Meter PWM Square Wave Signal Generator https://www.amazon.com/dp/B01HCXG9YS..._bfVYCbJRF6DKN

You can also order this kit with a case, but these things are actually really amazingly good for the cost. It will measure capacitance, ESR, inductance, and also tell you a lot about the random transistors and such that you might come across too. I think the accuracy of them really can't be beat for the cost..

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