Author Topic: How many uF this axial capacitor?  (Read 3325 times)

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Offline sdancer75Topic starter

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How many uF this axial capacitor?
« on: September 25, 2019, 05:55:21 pm »
Maybe it looks stupid but....

Is that white axial capacitor 1uF (2nd photo) ? I am not sure if I can decode the markings of this like 1/10 and 1.70MKP

Also the small smd in the 1st image, just beside the IC is also a capacitor; I get continuity on this part.
« Last Edit: September 25, 2019, 06:38:07 pm by sdancer75 »
 

Offline GreggD

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Re: How many uF this axial capacitor?
« Reply #1 on: September 25, 2019, 06:41:22 pm »
Looks like 1.7uF. It is large enough to be that.

Continuity, Some where else there is a resistor across the cap or some continuity through an IC
 
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Offline amyk

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Re: How many uF this axial capacitor?
« Reply #2 on: September 26, 2019, 01:44:15 am »
Google it first... https://www.tedss.com/2020043114 suggests you have a 0.1uF 250VAC  metalised polypropylene capacitor.
 
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Offline sdancer75Topic starter

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Re: How many uF this axial capacitor?
« Reply #3 on: September 26, 2019, 02:50:44 pm »
Google it first... https://www.tedss.com/2020043114 suggests you have a 0.1uF 250VAC  metalised polypropylene capacitor.

I measure 300nF and 0.85 ESR

So it seems impossible to have more capacity than originally had. Maybe it's an 1μF instead with 10% tolerance?
« Last Edit: September 26, 2019, 02:59:33 pm by sdancer75 »
 

Offline frozenfrogz

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Re: How many uF this axial capacitor?
« Reply #4 on: September 26, 2019, 03:13:17 pm »
1 µF, 10 % tolerance should be correct.
1.70MKP is the part series.
AV marking was from Arcotronics that are now owned by KEMET.

Edit for reference:
0.1 uF 10 % would be marked .1/10
0.33 uF 5 % -> .33/5
etc.
He’s like a trained ape. Without the training.
 
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Offline schmitt trigger

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Re: How many uF this axial capacitor?
« Reply #5 on: September 26, 2019, 03:40:41 pm »
The ceramic cap appears like a decoupling cap across pins 1 and 14, which are commonly used by Microchip as the Vdd and ground.

So if you are measuring "continuity", it means one of two things:
- somewhere across the many loads between +5v and ground there is a low impedance....it is not necessarily this particular capacitor that could be faulty.
- that your meter has a test voltage which could forward bias some semiconductor junctions.

 

Offline sdancer75Topic starter

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Re: How many uF this axial capacitor?
« Reply #6 on: December 12, 2019, 08:49:37 am »
Can I replace the original axial film capacitor 1uF/250V/10% with a ceramic 1uF/250V/10%?

This part is from a refrigerator control board.

Regards,
 

Offline TurboTom

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Re: How many uF this axial capacitor?
« Reply #7 on: December 12, 2019, 10:18:19 am »
The cap is likely a safety-rated component (X cap) due to the 250V~ spec. Don't replace it with a 250VDC rated part since it will probably fail (possibly in a spectacular manner) instantly or over a short time. Get the proper replacement!
 
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Offline sdancer75Topic starter

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Re: How many uF this axial capacitor?
« Reply #8 on: December 13, 2019, 09:26:58 am »
The cap is likely a safety-rated component (X cap) due to the 250V~ spec. Don't replace it with a 250VDC rated part since it will probably fail (possibly in a spectacular manner) instantly or over a short time. Get the proper replacement!

Hi,

The replacement part is Metallized Polypropylene Film and not ceramic as I wrote before sorry. It is not safety-X-rated cap but its also 250V and VDC. So, will this part work?

 

Online Gyro

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Re: How many uF this axial capacitor?
« Reply #9 on: December 13, 2019, 09:48:28 am »
No, that is a DC rating and the original is AC rated. The peak voltage of a 250V RMS AC sine wave is nearly 360V. You need to replace with at least 400V DC rating.
« Last Edit: December 13, 2019, 09:50:44 am by Gyro »
Best Regards, Chris
 
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Offline sdancer75Topic starter

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Re: How many uF this axial capacitor?
« Reply #10 on: December 23, 2019, 08:54:44 am »
No, that is a DC rating and the original is AC rated. The peak voltage of a 250V RMS AC sine wave is nearly 360V. You need to replace with at least 400V DC rating.

Maybe it's sound a stupid question, but how did you understand that Metallized Polypropylene Film capacitor above is DC rating. From the marking, I can only decode the capacity and the voltage rating. It does not say if is AC or DC.

A 400V Metallized Polypropylene Film will be a good replacement part for the original axial metalized polypropylene?
« Last Edit: December 23, 2019, 08:58:15 am by sdancer75 »
 

Offline mjkuwp

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Re: How many uF this axial capacitor?
« Reply #11 on: December 23, 2019, 12:19:40 pm »
The part has "250 V~" printed on it and the assumption is that "~" is a sine wave.  This is what suggests 250 V AC rating.
 
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Online Gyro

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Re: How many uF this axial capacitor?
« Reply #12 on: December 23, 2019, 01:02:17 pm »
Yes, if not explicitly indicated, assume that it is a DC rating - it is almost universally true.

The 250V~ marking is one of those exceptions, it normally applies to things like induction motor run capacitors, again where it will be very clearly indicated.
Best Regards, Chris
 
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Offline sdancer75Topic starter

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Re: How many uF this axial capacitor?
« Reply #13 on: December 23, 2019, 01:41:58 pm »
The part has "250 V~" printed on it and the assumption is that "~" is a sine wave.  This is what suggests 250 V AC rating.

Thank you for your answer but I meant the other part that has no indication at all but it clarified from Gyro !!
 

Offline gbaddeley

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Re: How many uF this axial capacitor?
« Reply #14 on: December 25, 2019, 08:02:29 am »
Agree with Gyro. Replacement needs to be 250VAC rated, 1.7uF. Preferably MKP for its self healing properties. A VDC rated cap could be used, but I would go over 400V for extra margin of safety, say 630V. You don’t want it to blow if there is an AC mains surge.
Glenn
 
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Offline sdancer75Topic starter

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Re: How many uF this axial capacitor?
« Reply #15 on: December 25, 2019, 08:47:21 am »
Agree with Gyro. Replacement needs to be 250VAC rated, 1.7uF. Preferably MKP for its self healing properties. A VDC rated cap could be used, but I would go over 400V for extra margin of safety, say 630V. You don’t want it to blow if there is an AC mains surge.

Thanks

Why are you mention 1.7uF instead of 1uF?

 

Offline gbaddeley

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Re: How many uF this axial capacitor?
« Reply #16 on: December 26, 2019, 11:39:21 am »
I stand corrected, 1.70MKP is a series designation. 1/10 indicates 1uF , 10%
Glenn
 
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