What charts should i consider for a capacitor

Thread Starter

Rocks45

Joined Jul 12, 2017
14
Hello iam trying to find out first if the frequency on the x axis charts for a capacitor is applicable to me since the capacitor is for a input voltage to a buck converter/DC circuit.Secondly if it does apply to me then using my multimeter on my input source i get 60Hz output from a AC to DC adapter iam using to power the Buck converter.Is my multimeter just a lie-o-meter at this point and its operating at a higher frequency?thanks
https://product.tdk.com/en/search/capacitor/ceramic/mlcc/info?part_no=CGA6N3X7R2A225K230AB
 

MrChips

Joined Oct 2, 2009
20,912
Your 60Hz AC to DC adapter takes 60Hz AC input and should provide DC output. What are your trying to measure with your multimeter? What range setting you have selected on your multimeter?

Show your circuit diagram of your buck converter.
Where is this capacitor in your circuit?
 

Thread Starter

Rocks45

Joined Jul 12, 2017
14
What charts are you talking about?
The charts in the link in my post only the frequency vs ESR/Impedance/Capacitance charts.
Your 60Hz AC to DC adapter takes 60Hz AC input and should provide DC output. What are your trying to measure with your multimeter? What range setting you have selected on your multimeter?

Show your circuit diagram of your buck converter.
Where is this capacitor in your circuit?
it does provide a DC output 5V,but when i switch to the Hz function on the multimeter i can get 60Hz on the DC side of the adapter.I cant grab the schematic till later but all it is a cap in parallel on the VIN pin on my buck converter.
 

MrChips

Joined Oct 2, 2009
20,912
The charts in the link in my post only the frequency vs ESR/Impedance/Capacitance charts.

it does provide a DC output 5V,but when i switch to the Hz function on the multimeter i can get 60Hz on the DC side of the adapter.I cant grab the schematic till later but all it is a cap in parallel on the VIN pin on my buck converter.
In that case, none of the charts apply to you.
 

Papabravo

Joined Feb 24, 2006
13,551
The charts in the link in my post only the frequency vs ESR/Impedance/Capacitance charts.

it does provide a DC output 5V,but when i switch to the Hz function on the multimeter i can get 60Hz on the DC side of the adapter.I cant grab the schematic till later but all it is a cap in parallel on the VIN pin on my buck converter.
Did you see the note where it said that it was reference data and did not guarantee that it would match the product? Ignore them. If you suspect they might be relevant you should get the actual data from the manufacturer or characterize the parts yourself.
 

Thread Starter

Rocks45

Joined Jul 12, 2017
14
So i double checked now i get random Hz reading on the Multimeter i even probed it 3 times all read solid 60Hz before.Its just a lie-o-meter,need to get a real measuring tool.
 

Thread Starter

Rocks45

Joined Jul 12, 2017
14
Did you see the note where it said that it was reference data and did not guarantee that it would match the product? Ignore them. If you suspect they might be relevant you should get the actual data from the manufacturer or characterize the parts yourself.
Ya i saw that i thought it would still work as a base reference or a general idea.There was a article i read from NI where he was designing a led board that went into a ceiling,but after a couple hours the lights would not work properly.Anyways he talked about how he found performance charts on the caps and apparently,The temperature dropped the cap value down to half its rated value. What he always thought was aslong as the material was X7R it would operate the same throughout the temperature range -55C to 125C which he found out is not true.What he said is always look at the charts for guidance of how the cap will operate in your application.Thats why iam so focused on the charts.I will look for the article and post it up.
 

Papabravo

Joined Feb 24, 2006
13,551
I think the mistake you made was to conflate a catalog page from a distributor with a datasheet from a manufacturer. Understanding how environmental factors affect component performance is essential to good design, and aid in debugging when things go wrong. I must confess that when I followed your link the first time I saw that it was a catalog page and did not scroll down to the charts. I apologize for that oversight.
 

Thread Starter

Rocks45

Joined Jul 12, 2017
14
I think the mistake you made was to conflate a catalog page from a distributor with a datasheet from a manufacturer. Understanding how environmental factors affect component performance is essential to good design, and aid in debugging when things go wrong. I must confess that when I followed your link the first time I saw that it was a catalog page and did not scroll down to the charts. I apologize for that oversight.
No apology needed,I feel like companies only want to do the minimum amount required.For example in a car they dont give you a extra spare ground wire or excess slack in the wires if they could get away without any wires at all they would.I feel like TDK gave us the charts because it was a minimum requirement to understand the capacitor behavior.Granted its not a guarantee accurate chart but iam sure they dont guarantee the value of the cap either.probably best to contact them direct like you said on specifics of the product.
 

Papabravo

Joined Feb 24, 2006
13,551
What the charts show is interesting from an academic point of view. The impedance chart shows impedance declining with frequency which is expected behavior. After reaching a minimum at some frequency the impedance begins to grow as the effect of parasitic inductance comes into play. If you have access to a network analyzer you can see the capacitor become an inductor at a sufficiently high frequency. It is kind of mind blowing when you think of it and is the reason lumped components cannot be used a sufficiently high frequencies.
 

ian field

Joined Oct 27, 2012
6,539
Hello iam trying to find out first if the frequency on the x axis charts for a capacitor is applicable to me since the capacitor is for a input voltage to a buck converter/DC circuit.Secondly if it does apply to me then using my multimeter on my input source i get 60Hz output from a AC to DC adapter iam using to power the Buck converter.Is my multimeter just a lie-o-meter at this point and its operating at a higher frequency?thanks
https://product.tdk.com/en/search/capacitor/ceramic/mlcc/info?part_no=CGA6N3X7R2A225K230AB
AFAIK: most multimeters can handle the AF range if you're lucky - but may only be good for mains frequency.

Capacitive and inductive reactance charts turn up from time to time - I usually find them while searching for other things.

Some component suppliers have a repository of this sort of thing, but it seems to be a waning trend.
 

EM Fields

Joined Jun 8, 2016
583
Hello iam trying to find out first if the frequency on the x axis charts for a capacitor is applicable to me since the capacitor is for a input voltage to a buck converter/DC circuit.
The capacitor you're referring to is most likely used for lowering the impedance of the DC source driving the buck converter, so the charts you;re referring to are probably irrelevant.
Secondly if it does apply to me then using my multimeter on my input source i get 60Hz output from a AC to DC adapter iam using to power the Buck converter.Is my multimeter just a lie-o-meter at this point and its operating at a higher frequency?thanks
Your DMM is probably operating properly, and it seems you might be introducing some cockpit error into the measurement by measuring frequency instead of DC voltage, since the 60Hz you're measuring is the ripple out of your AC to DC adapter, which is only doing half-wave rectification for some reason.
 
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