Re: [Amps] Rectifier equilization?

["Carl" <km1h@jeremy.mv.com>]

Ive measured the beginning of breakdown on a large number of diodes and the 
1N5408 PIV always falls in the 1300-1600V range. Its also a good reason why 
marginal PS designs survive.
Carl
KM1H



----- Original Message ----- 
From: "Alex Eban" <alexeban@gmail.com>
To: "'Vic K2VCO'" <k2vco.vic@gmail.com>; <amps@contesting.com>
Sent: Saturday, September 14, 2013 5:56 AM
Subject: Re: [Amps] Rectifier equilization?


> Neither are needed any longer.
> The capacitors were required because the recovery time of old rectifiers 
> was
> soo bad, that you could hear the noise generated in any close by 
> amplifier.
> This is no longer the case thanks to much improved manufacturing processes
> now in use.
> The resistors were needed because the junction capacitances were so
> different from diode to diode, that simply by voltage divider action the
> voltage spread across the diodes could cause some t exceed the PIV rating
> (the ones with lower junction capacitances). I remember measuring junction
> capacitance spreads of over 10 to one on diodes FROM THE SAME BATCH! It's 
> no
> longer the case today.
> Alex 4Z5KS
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Vic K2VCO
> Sent: Friday, September 13, 2013 7:54 PM
> To: amps@contesting.com
> Subject: Re: [Amps] Rectifier equilization?
>
> The resistors are definitely not needed. I used capacitors in my recent
> project in order to eliminate switching noise which might appear in my
> receiver -- I don't know if this was needed, since I didn't try it without
> the capacitors first!
>
> They should also provide some protection against transients, although I 
> also
> have MOVs in the primary.
>
> On 9/13/2013 9:28 AM, Hardy Landskov wrote:
> > I have just rejoined the amp list after a few years and am wondering
> > if the diode equalization question was ever resolved. I am building a
> > new bridge HV PS and it uses
> > 12 diodes per leg. Rich Measures says using a .01 & 470K across each
> > diode is no longer needed due to improvements in semiconductor manf.
> > processes. I have 100 1N5408's that came off the same reel so I feel
> > they should be matched fairly close. I would like to hear a few
> > opinions. Thanks 73 Hardy N7RT
> > _______________________________________________ Amps mailing list
> > Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
> --
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
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