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Cap_search
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Last Activity: 08-08-2023, 09:11 AM
Joined: 01-17-2013
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  • Cap_search
    replied to Values of ppm/°C of 2 resistors in parallel
    in General Electronics Technical Discussion
    Re: Values of ppm/°C of 2 resistors in parallel


    Hmm, so the tempco remains unchanged. Ok, thanks [B]eccerr0r[/B]!

    These are for emitter sensing resistors in a power amplifier (output stage).
    I'm asking because the value required is about 0.5Ω, but I have only 1Ω ones.

    And I thought because they were sharing same duty in parallel, then they could
    be/perform more stable through most loads or powers.

    Probably tempco is not critical in this application area.
    Thanks again! Much appreciated!Re: Values of ppm/°C of 2 resistors...
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    Last edited by Cap_search; 01-05-2021, 01:40 PM.

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  • Cap_search
    started a topic Values of ppm/°C of 2 resistors in parallel
    in General Electronics Technical Discussion

    Values of ppm/°C of 2 resistors in parallel

    First of all Happier New Year to all,

    Dear all, I hope I'm posting this in the right forum.

    Ok, I'd like to know the final ppm/°C of 2 identical resistors in parallel.

    Given two same resistors in parallel of, say, 1Ω (1W), both rated 300ppm/°C,
    I know their resistance will be 0.5Ω (2W), but will their [B]combined tempco[/B]
    value also be halved to 150ppm/°C ?
    Or their tempco will be increased to 600ppm/°C ??

    Thank you, any hint would be greatly appreciated! First of all Happier New Year to all,

    Dear
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  • Cap_search
    replied to Question about bipolar electrolytics
    in General Capacitor Questions & Issues
    That's what I thought, too. Just wondered they are usually bit larger than normal polarized equivalents. Grazie....
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    Last edited by Cap_search; 07-28-2019, 04:42 PM.

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  • Cap_search
    replied to Question about bipolar electrolytics
    in General Capacitor Questions & Issues
    Re: Question about bipolar electrolytics

    What about BP caps of 220uF or larger?
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  • Cap_search
    started a topic Question about bipolar electrolytics
    in General Capacitor Questions & Issues

    Question about bipolar electrolytics

    Good morning all,

    Is it true that all the bipolar electrolytics are made/manufacturered of [B]two[/B] "back-to-back" polar electrolytics in the - + + - configuration, and that would explain why they are usually larger than equivalent value of a common polarized electrolytic? (e.g. Muse UES)

    N.B.: polarized Silmic II are also usually larger than common electrolytic, though.Good morning all,

    Is it true that all the bipolar electrolytics are made/manufacturered of [B]two[/B] "back-to-back" polar electrolytics in the - + + - configuration,
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    Last edited by Cap_search; 07-22-2019, 02:48 AM.
  • Cap_search
    replied to Capacitor(s) Identification
    in General Capacitor Questions & Issues
    Re: Capacitor(s) Identification


    Thank you Pete,

    Do you think the yellow one is a metallized paper cap, or it's too small for that?
    Regards....
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  • Cap_search
    replied to Capacitor(s) Identification
    in General Capacitor Questions & Issues
    Re: Capacitor(s) Identification

    Sorry if I use this already open thread to ask about these caps, specially the yellow and blue ones (I know their values, but not the type)...

    The yellow is a 100nF (10% tol.) but that "50SN (in circle)" I couldn't identify.
    The blue is a 2.2F, but that "F" and "ND" I also couldn't identify.

    Not sure from where they came originally, probably a CD player (yellow) or from a PSU (blue), but I'm not sure......
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  • Cap_search
    replied to Samsung Syncmaster 225BW
    in Troubleshooting Computer Displays
    Re: Samsung Syncmaster 225BW

    I opened it today, just for a check, and wanted to measure the big cap [b]150uF/450V[/b]...

    Cap measured [b]119uF[/b]. That's why it always seemed not that "bright" enough. A new 180uF/450V is in it now. Monitor now is much better in terms of colour...Re: Samsung Syncmaster 225BW

    I opened it today, just for a check, and wanted to measure the big cap [b]150uF/450V[/b]...

    Cap measured [b]119uF[/b]. That's why it always seemed not that "bright" enough. A new 180uF/450V is in it now. Monitor now
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  • Cap_search
    replied to Differences in Voltage rates with same capacitance
    in General Capacitor Questions & Issues
    Re: Differences in Voltage rates with same capacitance



    Thank you so much, PeteS in CA!! ...
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  • Cap_search
    started a topic Differences in Voltage rates with same capacitance
    in General Capacitor Questions & Issues

    Differences in Voltage rates with same capacitance

    Good evening,

    Given a cap value of, say, 100uF/[B]10V[/B] (but can be any other), I'd like to know if there's much difference in (worse, better or no variation) performance comparing it to a, say 100uF/[B]50V[/B].

    I know it's (way!) safer to use the 50V rated version. But will it do a "better" job as it "should"? How the plates and dielectric are made and how they behave in different voltages?

    I'm curious about this, since 'modern' electrolytics are much smaller than their older (and vintage) counterparts, which some still do a really...
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    Last edited by Cap_search; 11-08-2018, 01:03 PM.
  • Cap_search
    replied to Samsung Syncmaster 225BW
    in Troubleshooting Computer Displays
    Re: Samsung Syncmaster 225BW

    Okay, from what I saw it's fine using higher value (but not much) as these Capxions drift a lot, and C113 can be a 220uF/35V.

    Nice monitor!
    See more | Go to post

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  • Cap_search
    replied to Samsung Syncmaster 225BW
    in Troubleshooting Computer Displays
    Re: Samsung Syncmaster 225BW

    Good evening all,

    Sorry to bring it up and perhaps this was already discussed, but here we go:

    1. is it mandatory to keep [B]same capacitance values[/B] (820uF, 680uF, 330uF, 47uF, etc) when replacing the caps? Or they can be increased by one value higher, e.g. 1000uF instead of 820uF, 470uF instead of 330uF, and so on?

    2. there's a "missing" cap in front of heatsink and regulator, I believe it's [B]C113[/B]. Someone told in an Youtube video that Samsung wanted to "cut costs" and didn't...
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  • Cap_search
    replied to Matsushita blue caps from 1991?
    in General Capacitor Questions & Issues
    Ok, thanks.

    2 more questions:

    - for what is the use [B]low leakage[/B] caps?

    - and so the [B]polymer hybrid[/B] caps?

    I see that the latter has much better numbers on endurance, ripple current, very low ESR, etc, over electrolytics...

    Example: [url]https://cdn.badcaps-static.com/pdfs/2ce4857b147261b6537fe6c8e48b8b6e.pdf[/url]Ok, thanks.

    2 more questions:

    - for what is the use [B]low leakage[/B] caps?

    - and so the [B]polymer hybrid[/B] caps?

    I see that the latter
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  • Cap_search
    replied to identifying film capacitors
    in General Capacitor Questions & Issues
    Re: identifying film capacitors

    Hi, from which amp/AV amp are these components? Yamaha?
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  • Cap_search
    replied to Matsushita blue caps from 1991?
    in General Capacitor Questions & Issues
    Film caps installed the right way


    Wow!

    I remember I had a couple of never fixed issues with amplifiers and now I start to think I might have installed some of them backwards!!

    I just got a bit confused with the markings: the "band" mark means that that polarity goes to the circuit, right? I don't have the instrument to see if the film cap has the flat line in the Xcope screen, though....
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    Last edited by Cap_search; 05-09-2018, 05:55 PM.

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  • Cap_search
    replied to Matsushita blue caps from 1991?
    in General Capacitor Questions & Issues
    Re: Matsushita blue caps from 1991?


    Yes, NAD also has Lelon caps in many later models... These earlier HK amps sound pretty good. But so far, all the green TK caps (pictured above) are measuring lower, so I'll replace all of them. ...
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  • Cap_search
    replied to Matsushita blue caps from 1991?
    in General Capacitor Questions & Issues
    Thank you very much guys. Yes, the caps in the first pictures (100uF/10V) are in the signal path. But these blue Matsushitas are pretty good indeed. Better than those "lavender" ones found in the vintage Technics gear from the 70's.

    The other ones (330uF/25V, rated 85*C) I mentioned are in the regulated PS for the preamp part of this brand TK - similar to the ones in the picture below. I will replace them with 390uF/35V ones rated 105*C, a lot of generated heat in that area also....
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  • Cap_search
    replied to Matsushita blue caps from 1991?
    in General Capacitor Questions & Issues
    Thank you very much, Agent. I kinda agree with you. There are some other caps in the local regulated supply (330uF) that are now lower in value (around 314uF) and I'm going to replace these with newer ones, so I though I could order a couple of Silmics just for the try.


    Hmmm, that's interesting. Thanks! ...
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  • Cap_search
    started a topic Matsushita blue caps from 1991?
    in General Capacitor Questions & Issues

    Matsushita blue caps from 1991?

    Hello to all,

    I have a question, maybe you can help me.

    I have a Harman Kardon amp from 1991 and the input caps are 100uF/10V to the power amp section. I measured both caps (left and right channels), they measured pretty ok on specs (~101uF). But these caps are spread out in the amp, so they look for generic use. I was thinking to replace them with some Silmic or Muse, but maybe there's no need as these blue Matsushtas might be of good quality for audio. What do you advise? ...
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