Help reading a schematic please

[bigal_scorpio]

Hi Eric and Ron,

Yes Eric, the 339s are cheap enough but it means either a longish trip to the nearest shop, or waiting till I have more stuff to order so I can get free postage!

Ron, as for Googling for another meter, I seem to have just about worn out my mouse, most links seem to be selling them, Peak for instance (which are great meters - I have their transistor/diode meter - present from the wife at Xmas!

As to designs for one, that is more difficult, some seem to be 8051 based which I can't do, and other links just lead to someone saying they made one but often have no schematics/diagrams.

I may have to wait for Xmas and put a few subtle hints to the wife, but I hate to be defeated by things, its not like I'm all that successful at much else to make up for it! hehehe

Regards............Al

 

[Roff]

Hi Eric and Ron,

Yes Eric, the 339s are cheap enough but it means either a longish trip to the nearest shop, or waiting till I have more stuff to order so I can get free postage!

Ron, as for Googling for another meter, I seem to have just about worn out my mouse, most links seem to be selling them, Peak for instance (which are great meters - I have their transistor/diode meter - present from the wife at Xmas!

As to designs for one, that is more difficult, some seem to be 8051 based which I can't do, and other links just lead to someone saying they made one but often have no schematics/diagrams.

I may have to wait for Xmas and put a few subtle hints to the wife, but I hate to be defeated by things, its not like I'm all that successful at much else to make up for it! hehehe

Regards............Al

Al, here are some schematics I found with Google. I have no idea if they work. You may have already seen some or all of them.

Equivalent Series Resistance Meter

Esr tester for capacitor

ftp://ftp.eskimo.com/u/m/mzenier/esrmeter.gif

**broken link removed**

Silicon Chip Online - Circuit Notebook

http://members.shaw.ca/swstuff/esrschematic.png

ePanorama.net

ePanorama.net

ePanorama.net

 

[bigal_scorpio]

Some success at last!

Hi Guys,

At long last after nearly a month of debugging this circuit I have it running, b ut with a small problem, however much I adjust the 4k7 trim pot I cannot get a correct capacitance reading! EG a 470uF cap reads 4.7uF.

Can anyone tell me the part of the circuit that is likely to be the cause of this problem. I have checked and rechecked the resistor values and they all seem ok, so do the transistors.

If anyone can help please feel free to suggest anything that may be wrong or any errors in the circuit.

Eric, when you had the simulation running did the values of the test cap and reading tally up?

Thanks for looking guys.................Al

 

[ericgibbs]

Eric, when you had the simulation running did the values of the test cap and reading tally up?
Al

hi Al,
On simulation it isnt possible to calculate/measure real values.

I have project board on the shelf set up with a 16F628A and 3.2768Mhz xtal.
I'll knock up the 'cap test' osc logic and give it a try, get back to you.

The 470uF cap, did you try it both ways around, [its a polarised electrolytic], on the test probes.

What reading do you get for say 0.47uF ceramic.?

 

[bigal_scorpio]

hi Al,
On simulation it isnt possible to calculate/measure real values.

I have project board on the shelf set up with a 16F628A and 3.2768Mhz xtal.
I'll knock up the 'cap test' osc logic and give it a try, get back to you.

The 470uF cap, did you try it both ways around, [its a polarised electrolytic], on the test probes.

What reading do you get for say 0.47uF ceramic.?

Thanks Eric,

Yes I tried both ways and same result! Strange

As for 470n nearest I could lay hand on easily was a 1.8uF polyester and that shows 0.00000000.

I have a feeling something is either way too small or way too big mate, but don't know what.

BTW As you suggested I have dispensed with the front end of the circuit and now am running from a 7805 instead of all the gubbins the author used. Also no backlight required or credits, so also dispensed with.

Good of you to test for me mate, thanks............Al

 

[ericgibbs]

hi Al,

Looking thru my 'AlsStuff' folder, which circuit are you referring too.

Is the LCF or the ESR meter.

If its the LCF I can do that fairly quickly, but if its the ESR I have doubts about that circuit/program ever being able to measure a capacitors ESR.!!!

 

[bigal_scorpio]

Hi Eric,

Its the ESR circuit, the one at the first thread in this post mate.

Regards Al

 

[ericgibbs]

Hi Eric,

Its the ESR circuit, the one at the first thread in this post mate.

Regards Al

OMG.
I thought you had consigned that to the recycle bin.

I still believe that the ESR project was a students assignment and most likely never worked.

There are so many errors/omissions on the circuit diagram, I suspect the program could be the same.
The results you have posted for the test capacitors, ie 470uF and the 1u8F caps suggest the program
and method of measurement is unproven.

 

[bigal_scorpio]

Hello again Eric,

I would have as you said have binned the project but alas its the only one I could find on the entire web which didn't require an micro amp analogue meter, and the only meter I have is a 50 milliamp one.

Seeing as I had all the bits for it I thought I would plod on with it, and indeed after only a month of trying I got a reading! I admit its the wrong one but I was so happy to get anything that I was spurred to carry on.

I do really need an ESR meter mate, some caps I tested with the cap meter later decided to set alight, even though they tested perfect on capacitance, and a major fire was only averted because my mate was there at the time and turned off his power quickly!

So I need to get something working to avoid that happening again! I don't feel I could trust a cap again without checking its ESR, I wouldn't be able to sleep knowing that I could have caused someone to be incinerated.

Anyway Eric, any suggestions or help would be much appreciated and I will live in hope of getting a circuit for ESR working eventually.

Regards..............Al

 

[Nigel Goodwin]

Buy the Peak Electric one, you even live fairly close to where they are made (Buxton), it's so much better than the home made ones (I have both).

 

[bigal_scorpio]

Buy the Peak Electric one, you even live fairly close to where they are made (Buxton), it's so much better than the home made ones (I have both).

Hi Nigel,

I agree about the Peak testers, I do have a Peak DCA55 that my wife bought me last Xmas and its excellent, but at the moment its the old time or money equation! No money but spare time!

I do live fairly close to Buxton but unless they do a very favourable discout for living near them I can't afford one yet

Saying that, I also live close to you, and maybe you don't want your "inferior home made ESR meter" hehehe

Al

 

[Nigel Goodwin]

Saying that, I also live close to you, and maybe you don't want your "inferior home made ESR meter" hehehe

You live considerably closer to me!

Funnily enough, I do have one partially built at home, when I built my original one at work I started building one for myself as well - but never finished it. But knowing where it might be is a differeent matter?.

 

[bigal_scorpio]

You live considerably closer to me!

Funnily enough, I do have one partially built at home, when I built my original one at work I started building one for myself as well - but never finished it. But knowing where it might be is a differeent matter?.

Hi Nigel,

Well if you do happen to come across it give me a shout!

It would be nice to meet one of the members in person, but will I recognise you without your martial arts gear on?

Seriously though, slipping over to your neck of the woods isn't a problem mate.

Al

 

[ericgibbs]

Hello again Eric,

I would have as you said have binned the project but alas its the only one I could find on the entire web which didn't require an micro amp analogue meter, and the only meter I have is a 50 milliamp one.
Al

hi Al,
Just checked my stock I have a brand new 100uA FSD analog meter, scaled 0 to 3 and 0 to 10.
Its a freestanding meter in its own case.

You have my email, send me your address if you want it, its yours free gratis.

Excuse the poor image, I had all my decent camera kit stolen in Jo'burg 5 years ago, replaced it with a el-cheapo.

 

[Nigel Goodwin]

It would be nice to meet one of the members in person, but will I recognise you without your martial arts gear on?

You really don't want to meet me naked!

 

[bigal_scorpio]

hi Al,
Just checked my stock I have a brand new 100uA FSD analog meter, scaled 0 to 3 and 0 to 10.
Its a freestanding meter in its own case.

You have my email, send me your address if you want it, its yours free gratis.

Excuse the poor image, I had all my decent camera kit stolen in Jo'burg 5 years ago, replaced it with a el-cheapo.

That would be great Eric, I will email you the details and will gladly reimburse you any costs, if you have a PayPal account it I can send it immediately.

Anyway I am going to email you with my details now.

Thanks again Eric....................Al

 

[bigal_scorpio]

Update for Eric

Hi again Eric,

Just to let you know that the email you will get is from my wifes email address!

For some unknown reason my own emails have stopped working, which is a common occurance with this provider! Though how mine can be broken and hers still works fine is always a baffler!

Al

 

[bigal_scorpio]

You really don't want to meet me naked!

Hi Nigel,

If only I wasn't a happily married man! hehehehe

Al

 

[Nigel Goodwin]

hi Al,
Just checked my stock I have a brand new 100uA FSD analog meter, scaled 0 to 3 and 0 to 10.
Its a freestanding meter in its own case.

Did you steal it from school Eric?

Nice meter, from RS Components, which of course they weren't called when you (or me) were at school.

 

[ericgibbs]

Did you steal it from school Eric?

Nice meter, from RS Components, which of course they weren't called when you (or me) were at school.

hi,
I have had that meter IIRC, since about 1970, never used it, still in its original box.!
Sadly a long time after my school days which ended in 1946.....

As I posted the other day, the first RS catalog I saw, was A6 size, about a dozen pages. RF coils and solid dielectric tuning caps.

I did have some pre war Camm's comics, gave them to a guy who lectures on classical electronics.

EDIT: 1948 >> 1946 !