capacitor ripple vs endurance & other questions

[PCBONEZ]

Re: capacitor ripple vs endurance & other questions

I could never see the chalkboard in math class.

Not ~really~ but close enough at 100kHz.

Lets run an example cap through the math so everyone finally gets it:
I chose a 1500uF 6.3v MBZ with ESR = 0.026 Ohms
[Middle of the normal range of caps on mobos and Rubycon gives actual ESR in data sheet vs Impedance.]

Z = Impedance
C = 1500 uF = 0.0015 F
ESR = .026 Ohm [squared = 0.000676 Ohm]
ƒ = 100 kHz = 100,000 Hz [Data sheet standard.]
p = PI = 3.14159
10 nH = 0.00000001 H
-- nH guessed as reasonable based on other reading. Is physical size dependent.
-- Lytics range from 4 nF for an itty bitty to 34 nF for a beer can cap.]

XC= 1 ÷ 2pƒC
2pƒC = 2 x 3.14159 x 100000Hz x 0.0015F = 942.477
XC = 1 ÷ 942.477 = 0.001061
XC = 0.001061

XL = 2pƒL
XL = 2pƒL = 2 x 3.14159 x 100000Hz x 0.00000001H = 0.006283
XL = 0.006283

(XL - XC) = 0.005222
(XL - XC)² = 0.0000273

Z² = ESR² + (XL - XC)² = 0.000676 + 0.0000273 = 0.0007033
Z² = 0.0007033
Z = 0.0265

Z is only 0.0005 different from ESR at 100kHz
That's less than 2% different.
.

[Toasty]

Re: capacitor ripple vs endurance & other questions

[mockingbird]

Re: capacitor ripple vs endurance & other questions

I could never see the chalkboard in math class.

[PCBONEZ]

Re: capacitor ripple vs endurance & other questions

Ahh.. so impedance is ESR. I was looking for Electrostatic Resistance.

Not ~really~ but close enough at 100kHz.

Lets run an example cap through the math so everyone finally gets it:
I chose a 1500uF 6.3v MBZ with ESR = 0.026 Ohms
[Middle of the normal range of caps on mobos and Rubycon gives actual ESR in data sheet vs Impedance.]

Z = Impedance
C = 1500 uF = 0.0015 F
ESR = .026 Ohm [squared = 0.000676 Ohm]
ƒ = 100 kHz = 100,000 Hz [Data sheet standard.]
p = PI = 3.14159
10 nH = 0.00000001 H
-- nH guessed as reasonable based on other reading. Is physical size dependent.
-- Lytics range from 4 nF for an itty bitty to 34 nF for a beer can cap.]

XC= 1 ÷ 2pƒC
2pƒC = 2 x 3.14159 x 100000Hz x 0.0015F = 942.477
XC = 1 ÷ 942.477 = 0.001061
XC = 0.001061

XL = 2pƒL
XL = 2pƒL = 2 x 3.14159 x 100000Hz x 0.00000001H = 0.006283
XL = 0.006283

(XL - XC) = 0.005222
(XL - XC)² = 0.0000273

Z² = ESR² + (XL - XC)² = 0.000676 + 0.0000273 = 0.0007033
Z² = 0.0007033
Z = 0.0265

Z is only 0.0005 different from ESR at 100kHz
That's less than 2% different.
.

[mockingbird]

Re: capacitor ripple vs endurance & other questions

Ahh.. so impedance is ESR. I was looking for Electrostatic Resistance.

[PCBONEZ]

Re: capacitor ripple vs endurance & other questions

WOW!! KZE is higher ESR than FM!!!! Is KZG any better? Sorry for not looking at the spec sheets myself, I don't understand how to calculate ESR from a spec sheet.

Yup,

The interesting thing is, if you buy in lots of 10pc or more then many times FM are less expensive than caps with less good ratings.
-
Only problem is sometimes FM are big for their uF and so won't fit.

[Toasty]

Re: capacitor ripple vs endurance & other questions

Here:

[Toasty]

Re: capacitor ripple vs endurance & other questions

WOW!! KZE is higher ESR than FM!!!! Is KZG any better? Sorry for not looking at the spec sheets myself, I don't understand how to calculate ESR from a spec sheet.

Calculate? There is no calculate. Just read the datasheets.

[yyonline]

Re: capacitor ripple vs endurance & other questions

WOW!! KZE is higher ESR than FM!!!! Is KZG any better? Sorry for not looking at the spec sheets myself, I don't understand how to calculate ESR from a spec sheet.

KZG is equivalent spec-wise to MBZ/WG. However, it's not recommended for recapping purposes has KZG is prone to failure.

[mockingbird]

Re: capacitor ripple vs endurance & other questions

WOW!! KZE is higher ESR than FM!!!! Is KZG any better? Sorry for not looking at the spec sheets myself, I don't understand how to calculate ESR from a spec sheet.

[GameBooy2020]

Re: capacitor ripple vs endurance & other questions

Thank you. This was very helpful. I've been struggling to understand why people recommend which series for what.

Yeah same here, the information everyone has placed here has helped me alot. I finally understand what all of the values are and what they do now. Thanks guys!

[PCBONEZ]

Re: capacitor ripple vs endurance & other questions

Thank you. This was very helpful. I've been struggling to understand why people recommend which series for what.

One question though. When are you recommending KZE and MBZ/MCZ?

This is the way I understand it. KZE and MBZ/MCZ are Low ESR and high ripple caps. So you use them in places where low ESR is required like a motherboard's VRM. Would you put KZE let's say on a power supply?

KZE is in fact intended for PSU according to Chemicon.

Looking at 8x20mm

MCZ: .................... 2350 / .012
FL & FJ: ................. 1870 / .016
MBZ & WG: ........... 1870 / .019
FM: ....................... 1560 / .030
KZE, ZL, WX, HD: . 1250 / .041
KY, HE: ................. 1050 / .069
FC, PW: .................. 995 / .065
LXZ: ....................... 810 / .080

The 10x20mm follow the same pattern.

In Vcore and RAM:
KZE was the typical grade on PC133 motherboards.
By DDR RAM MBZ was more typical.
- It varies with how many cap are used because caps in parallel lowers total circuit ESR.

KZE grade is still common for the 8 & 10 mm caps used out near the add-in slots when the board has 6 or more caps out there.
Low cap-count boards will use higher grades.

.

[Toasty]

Re: capacitor ripple vs endurance & other questions

Here:

https://www.badcaps.net/forum/showpo...11&postcount=4

I did my own chart based on his info using only readily available caps from USA suppliers. No types that are N/A in US without extraordinary effort. Like Pana FJ or FL.

[Toasty]

Re: capacitor ripple vs endurance & other questions

He's only posted that info ohhhh 50 times now......

There is also a chart PC did on replacements based on application and quality/ratings. Buried in another thread and posted within past year IIRC. If I find it, I'll put the link here.

[mockingbird]

Re: capacitor ripple vs endurance & other questions

Thank you. This was very helpful. I've been struggling to understand why people recommend which series for what.

One question though. When are you recommending KZE and MBZ/MCZ?

This is the way I understand it. KZE and MBZ/MCZ are Low ESR and high ripple caps. So you use them in places where low ESR is required like a motherboard's VRM. Would you put KZE let's say on a power supply?

[PCBONEZ]

Re: capacitor ripple vs endurance & other questions

The ratings to look at beyond uF and volts are ESR and Ripple.
[Remember going up in volts isn't a problem.]

ESR is isn't really Impedance (Z) - but:
At the 100kHz they use for data sheets Xc and ESL are at values such that *effectively* ESR = Impedance.
The actual equation is:
Z² = ESR² + (XL - XC)²
[Note: (XL - XC) must be corrected to a positive value if it isn't.]
-
ESR is effectively a measure of the cap's 'resistance' to AC Ripple.
Since the cap's job is to short Ripple out to ground: lower is better.

The 'Ripple' rating tells you how much Ripple current the cap can pass without overheating internally.
It is the capacitor equivalent of a watt rating on a resistor.
It tells you how 'heavy duty' the cap is and thus: more[higher] is better.

elite PF ------ 1000uf @ 16V ( 10 x 20 mm) - General Purpose cap - Ripple = 680
Rubycon PX @16v is not rated good enough.[Ripple = 640]
I would use something like LXZ, LXY, VZ, FC, PW

Capxon KF --- 1000uf @ 10V ( 10 x 16 mm) 1040 / 0.076
Panasonic FC is just good enough for this one. [KF specs are not linear, so to speak.]
Use FC or better.

capxon KF --- 470uf @ 10V ( 8 x 11.5 mm) 580 / 0.250
capxon KF --- 470uf @ 25V ( 10 x 16 mm) 1200 / 0.076
These are rated better than FC.
Chemicon KY or Nichicon HE are good enough.
Chemicon KZE and Rubycon ZL are the next better grade.

Sacon FZ ---- 330uf @ 16V ( 8 x 12 mm) - 1150 / 0.036
Pannasonic FM is not good enough. [950 / 0.056]
Use Rubycon MBZ or MCZ - Panasonic FJ or FL - Sanyo WG.

skywell SHT - 1000uf @ 6.3V ( 10 x 12 mm (not sure about height since I could'nt find data sheet for SHT) )
I would treat this the same as the FZ to be safe since I can't find a spec sheet either.

.

[mockingbird]

Re: capacitor ripple vs endurance & other questions

KF I replace with UCC LXZ or LXY

[GameBooy2020]

Re: capacitor ripple vs endurance & other questions

I see, so endurance is practically useless, thanks for clearing that up for me.


here's a list of the old capacitors that I plan to replace:

brand -------- specs

elite PF ------ 1000uf @ 16V ( 10 x 20 mm)
capxon KF --- 1000uf @ 10V ( 10 x 16 mm)
capxon KF --- 470uf @ 10V ( 8 x 11.5 mm)
capxon KF --- 470uf @ 25V ( 10 x 16 mm)
skywell SHT - 1000uf @ 6.3V ( 10 x 12 mm (not sure about height since I could'nt find datasheet for SHT) )
Sacon FZ ---- 330uf @ 16V ( 8 x 12 mm)


The capxon's and the elite are from lcd monitor power supplies, and the skywell & sacon caps are from video cards (AGP).

[PCBONEZ]

Re: capacitor ripple vs endurance & other questions

I apologize, here are the values of the capacitors that I need and the sizes as well:

330 uf @ 16 V ----------- 8 x 12 mm
1000 uf @ 6.3 V ---------- 10 x 12 mm
1000 uf @ 10 V ---------- 10 x 16 mm
470 uf @ 25 V ---------- 10 x 16 mm
470 uf @ 10 V ----------- 8 x 11.5 mm
1000 uf @ 16 V ------------ 10 x 20 mm

What make and series were the old ones?

What is the application?

.

[PCBONEZ]

Re: capacitor ripple vs endurance & other questions

Hey thanks for replying!

So even though endurance is not tested in a typical operating condition, wouldn't a capacitor rated at 4000 hours @ 105C be better than a capacitor rated at 2000 hours @ 105C?

As I said, endurance tells you nothing useful about actual lifetime.

For the explanation lets say all the caps other characteristic are the same such that the useful lifetime follows the endurance lifetime.

As so:
Cap 1 - 2000hr => 6 year useful lifetime
Cap 2 - 4000hr => 12 year useful lifetime.

But because of the +/-40% accuracy...
6 years really means from 3.6 to 8.4 years and useful lifetime would be as expected.
12 years really means from 7.2 to 16.8 years and useful lifetime would be as expected.

Every single Cap 2 could fail at 7.2 years.
Every single Cap 1 could last 8.4 years.

Did the Endurance number help you? - NOPE!

.