Geometrical dimensions: L = 7.2 mm, W = 2.4 mm, H = 6.5 mm, connector pitch = 5.5 mm +-.5 mm

Color: white

No further information printed onto the capacitor

4 of these capacitors are used at on end of an IC ULN2804A and ULN2804A

I thanking you in advance for helping comments!!!

]]>I don’t really know if my formula is correct. I thought it was just slight mistake, so it was more as a guess based on units of variables used in the previous formula.

If my guess is correct then yes, your calculations seem fine but i would skip dividing by 1000000 in second part bc it cancels itself out anyways.

((peakcurrent/(mmcCapacitance/1000000))/1000000)) = peakcurrent/mmcCapacitance (in uF)

]]>I think my errors goes a bit deeper. The MMC rating dv/dt calculation also uses the primary peak current and not the MMC peak current rating. This is all reflected into the MMC calculator as well, where the calculation for MMC rating is actually the correct one for what the should be in the actual values. https://kaizerpowerelectronics.dk/calculators/mmc-calculator/

70000 hz, with your correct formula

2527 v 1111 dv/dt

For MMC calc (dVdtRating=((peakcurrent/(mmcCapacitance/1000000))/1000000); )

2592A and 0,15 uf

17280 dv/dt

Would love if you could double check before I make the corrections ðŸ™‚

Kind regards

Mads

Charles above was right

with method written in your tutorial it came out as:

[Hz] = 1/s

[dV/dt] = [V/Hz] = [V/(1/s)] = [Vs], not [V/s] how it was suppose to be

I think proper method should look like this:

[dV/dt] = [V*Hz] = [V*(1/s)] = [V/s]

(I omitted unnecessary constants)

]]>there is a small mistake in your dV/dT calculations, with exact same numbers that you put in there i get result equal to 0.35903916. Even by moving order of magnitude higher it’s still off

]]>I agree on the 4.7uF value, as its also marked on the PCB in white text “4uF7”. 100V voltage rating is correct and UD is just some manufacturing date code or other manufacturer specific code, do not worry about that ðŸ™‚

Kind regards

Mads

I would really appreciate your help. I have uploaded a photo of damaged capacitor that I would like to replace.

I have tracked down a (1st line) 4.7, (2nd line) 100v (3rd line) VT.

Is the VT on the sourced Cap. of significance in using as a replacement for the original with UD on it?

The equipment I want to repair is an Inductive Heater used for heating/releasing seized/corroded car components.

Hope you can help.

Mike ]]>

Looking forward to see the finished result. Thank you for sharing ðŸ™‚

Kind regards

Mads

I think you are right about all the values, KC has been used for “kilo cycles” in some components, for stating a maximum working frequency, but on your capacitor it is the voltage rating and KC is properly some manufacturing specific code.

Was the 1.8mH lid like ferrite metal or plastic? If its ferrite, it was a part of getting the rated inductance and you need to replace it.

Generally there is not much sound difference in the different metal film capacitor technologies, when in the same voltage and rating. Measurements will show if there is a difference, not listening, I only believe in measurements.

Kind regards

Mads