Re: Low ESR Capacitors


Gordon REASON <gordonj.reason@...>
 

I made one up , from a simple circuit , taken fron google .........

Analogue panel meter ........ works fine .........

get's used about every five years or so , if I can find it !

On 27 June 2020 at 16:40 "Michael Scott via groups.io" <g3lyp@...> wrote:

Following the recent discussion on low ESR capacitors ( 7L18 ), what is a reliable method of measurement of ESR? Peak do a meter for around £100, but there are several cheaper multimeters which claim to be able to measure ESR.
 
Has anyone any advice/experience of these devices.
 
I am asking because the subject has come up recently when I have been asked for capacitors from the Chipbank for Sam’s Iceni and other transverters. Many of the capacitors I have in stock were given to me in plastic pots with no information other than the capacitance value. Sam specifies COG/NPO for most of his designs, and in some cases I have reels where the spec or code is given and I can track back to a datasheet, but for the loose ones it is pot luck what you get!
 
73,
 
Mike G3LYP
 
From: Paul G8KFW
Sent: Saturday, June 27, 2020 2:54 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?
 

Hi

 

This is a subject that has been talked about a lot over the last 2 plus years on the HP Groups

 

and in general unless it is a switch mode power supply the replacement with a good quality ( not a copy ) non tantalum is considered a good replacement

But Low ESR capacitors  are quit often required for switch mode power used on certain HP equipment   but they are a lot more expensive

 

Regards Paul

 


From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of Paul Randall G3NJV
Sent: 27 June 2020 09:24
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?

 

Ditto for three Racal 1792 receivers I acquired. Dozens of tantalum caps faulty. I'd say,  if you find more than one or two faulty,  bite the bullet and replace the lot. 

Question,  what's the opinion on what type to use for the replacements?

Paul

 

-------- Original message --------

From: Paul G8KFW <paul@...>

Date: 26/06/2020 23:57 (GMT+00:00)

To: UKMicrowaves@groups.io

Subject: Re: [UKMicrowaves] 7L18?

 

Hi Ben

 

The last 7L18 I worked on required replacement of a large number of  Tantalum capacitors

 

Suggest you get an ESR meter and look at all the caps first don’t unsolder them just do the testing in CCT  and record the results

Then replace the suspect ones

 

Regards Paul B

 


From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of militaryoperator via groups.io
Sent: 26 June 2020 22:35
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 7L18?

 

Does anyone have experience of working on the 7L18 spectrum analyser in the 7603 mainframe?

 

Only mine has a problem.

 

Ben

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Military Wireless Museum

Kidderminster , UK .

 

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