How many uF this axial capacitor? - Page 1
Forum section: electronics / projects

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 25, 2019, 05:55:21 pm
content: 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 1.70MKPAlso the small smd in the 1st image, just beside the IC is also a capacitor; I get continuity on this part.

author: GreggD
author_rank: Regular Contributor
timestamp: September 25, 2019, 06:41:22 pm
content: 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

author: amyk
author_rank: Super Contributor
timestamp: September 26, 2019, 01:44:15 am
content: Google it first...https://www.tedss.com/2020043114suggests you have a 0.1uF 250VAC metalised polypropylene capacitor.

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 26, 2019, 02:50:44 pm
content: Quote from: amyk on September 26, 2019, 01:44:15 amI measure 300nF and 0.85 ESRSo it seems impossible to have more capacity than originally had. Maybe it's an 1μF instead with 10% tolerance?

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: September 26, 2019, 03:13:17 pm
content: 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 .1/100.33 uF 5 % -> .33/5etc.

author: schmitt trigger
author_rank: Super Contributor
timestamp: September 26, 2019, 03:40:41 pm
content: 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.

author: sdancer75
author_rank: Frequent Contributor
timestamp: December 12, 2019, 08:49:37 am
content: 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,

author: TurboTom
author_rank: Super Contributor
timestamp: December 12, 2019, 10:18:19 am
content: 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!

author: sdancer75
author_rank: Frequent Contributor
timestamp: December 13, 2019, 09:26:58 am
content: Quote from: TurboTom on December 12, 2019, 10:18:19 amHi,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?

author: Gyro
author_rank: Super Contributor
timestamp: December 13, 2019, 09:48:28 am
content: 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 withat least400V DC rating.

author: sdancer75
author_rank: Frequent Contributor
timestamp: December 23, 2019, 08:54:44 am
content: Quote from: Gyro on December 13, 2019, 09:48:28 amMaybe 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?

author: mjkuwp
author_rank: Unknown
timestamp: December 23, 2019, 12:19:40 pm
content: 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.

author: Gyro
author_rank: Super Contributor
timestamp: December 23, 2019, 01:02:17 pm
content: 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.

author: sdancer75
author_rank: Frequent Contributor
timestamp: December 23, 2019, 01:41:58 pm
content: Quote from: mjkuwp on December 23, 2019, 12:19:40 pmThank you for your answer but I meant the other part that has no indication at all but it clarified from Gyro !!

author: gbaddeley
author_rank: Regular Contributor
timestamp: December 25, 2019, 08:02:29 am
content: 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.

author: sdancer75
author_rank: Frequent Contributor
timestamp: December 25, 2019, 08:47:21 am
content: Quote from: gbaddeley on December 25, 2019, 08:02:29 amThanksWhy are you mention 1.7uF instead of 1uF?

author: gbaddeley
author_rank: Regular Contributor
timestamp: December 26, 2019, 11:39:21 am
content: I stand corrected, 1.70MKP is a series designation. 1/10 indicates 1uF , 10%