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Old 1st Dec 2011, 10:22 pm   #61
Top Cap
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Default Re: My Homebrew ESR Meter for testing el caps

Sorry to learn of your problems, I managed to get the meter to work with a 100uA meter. Have you sufficient drive on the collector of the 2N2222, should be around 2V at 156kHz. Not sure if increasing the 0.1 capacitor closer to its 0.47 design would help but worth trying putting another 0.1 across it to see if it increases output to any degree. All I can otherwise suggest is check all components are correct including the bridge rectifier diodes. Its the silly but very elusive mistakes that can make one lose confidence in a circuit, I have built a couple on my Vero board design and they both worked fine, pcb is better if you don't use strip board very often as there is less chance of error. The overall design of the instrument is sound.
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Old 2nd Dec 2011, 8:14 am   #62
John M0GLN
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Default Re: My Homebrew ESR Meter for testing el caps

As in my post #57, I have mine working with a 500μA meter, I just added an emitter bias capacitor which increased the output quite a bit, but still insufficient for the meter, so I decreased the emitter resistor until I got over FSD and just set zero with the variable resistor, I left R17 out and just relied on the variable resistor, but if you do this, make sure you start with it set at maximum or you could damage the meter.

John
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Old 6th Dec 2011, 12:40 am   #63
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Default Re: My Homebrew ESR Meter for testing el caps

David G4EBT and all others on this thread. Thanks for this circuit and all the comments left here. I have finally finished my ESR meter and have it working. I have checked several caps that I know to be bad and this is what I found.
(2) 470uF (with swelled tops) check GOOD but with a Fluke meter the capacitance checks around 223uF NOT GOOD.
(3) 1000uF caps (with swelled tops) which do check bad at about 10 on my ESR meter.
Why is this with the 470uF caps can anyone answer my question?
I have another question for someone. Here it goes I modded my meter to run off 9v batt or 9v AC/DC adapter but when I plug the adapter in the meter jumps to about quarter scale and with leads shorted won't go above 3/4 scale Cananyone tell me why that is?
I have posted some pic's of my meter.

Thanks!
Kevin KI4GWZ
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Old 7th Dec 2011, 12:38 am   #64
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Default Re: My Homebrew ESR Meter for testing el caps

I figured out the problem with the adapter. I had to fit a 1uF capacitor before the 78l05. New question can anyone tell me how to open the scale of the meter on the FSD side? I want instead of 0 to .5 to 1 and so on. I want it to look more like 0 to .1 to .2 to .3 and so on.

Kevin KI4GWZ
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Old 14th Feb 2012, 10:30 pm   #65
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Default Re: My Homebrew ESR Meter for testing el caps

Here's my version of the popular ESR Meter.

All components except the 5V regulator the IC and the battery have been recycled.

As you can see the meter scale is a hybrid. I should really have asked my wife to write on the numbers for a neater job.I got lucky with the 1 and 5 since they conveniently fell at printed scale points.I had to fiddle about to get the 12 ohm point.

The 50uA meter was rescued from an old Pye R7AM receiver.I used a 20k ohm pot to set FSD and R17 was linked out.

The die cast box was a battery tester for ITT Starphone batteries,the front panel is a piece of scrap aluminium pop riveted on to cover unwanted holes.The veroboard is at least 30 years old and was a remnant from a synthesizer project.

The rest of the components have been salvaged from all sorts of discarded bits of equipment.
This might not be the best looking meter on the forum but it may be up there for the "cheapest to build" rosette.

Thanks go to Dave for highlighting this simple but very useful piece of test gear and to Top Cap for his vero board layout.

John
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Old 8th Jun 2012, 5:37 pm   #66
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Default Re: My Homebrew ESR Meter for testing el caps

Following on from requests, I have changed the strip-board version slightly so that a SIL Resistor pack is not required.
Les
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Old 10th Jun 2012, 5:02 am   #67
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Default Re: My Homebrew ESR Meter for testing el caps

I think there might be a missing PCB top that shows parts and layout.

You mention there is no cap at C7, but on the authors parts it's there between TP6 and TP1 10u,

You mentioned the 22K Zero Pot(The zero pot isn't actually shown on the circuit - it needs to be fitted between TP 3 and the meter + connection)., but on the updated xray in green shows it to be connect to TP4.

Will a 33u 400VDC Cap work or does it have to be 0.47? Will it work if one is not used?

Thanks for your time.
Bob
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Old 10th Jun 2012, 5:20 am   #68
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Default Re: My Homebrew ESR Meter for testing el caps

Sorry, I also meant to mention, I'm having trouble locating C10 unless it's actually C7.

Thanks
Bob
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Old 20th Mar 2014, 8:58 pm   #69
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Default Re: My Homebrew ESR Meter for testing el caps

Hello Folks

i just soldered the version from Top Cap with standard resistors. Unfortunately there is no output where the meter is connected, also tried with my multimeter which i know works.

Instead of 2N222 i used an BC547 and instead 74HC14N used an 40106. Instead 1N4004 i used 1N4007.
http://www.nxp.com/documents/data_sheet/HEF40106B.pdf
http://www.datasheetcatalog.com/data.../4/BC547.shtml

Till now i verified that the input voltage on 40106 is 5V. But 78L05 really gets kind of hot, at least 60°C.

Then i measured where it says 250mV after 680Ohm resistors, i get only 28mV DC. Anyone willing to help
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Old 21st Mar 2014, 1:45 am   #70
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Default Re: My Homebrew ESR Meter for testing el caps

Hi xrated2, You will need to fit a 74HC14 as it has the drive capability of +/- 25mA which the CD40106 does not, this is only 1mA or less. The 78L05 is quite capable of working here so check for any track shorts from solder spills or incorrectly broken tracks. Make sure all polarised components like the diodes are the right way round and re-check all component wire positions on the board as it is easy to fit for example a diode into the wrong hole.
Using five 680 ohm resistors is OK, all summed together and fed to where pin 1 of the SIL resistor pack is connected. I did do an alternative layout for standard resistors but not sure if you can use the same board, you may have to knock up another piece of board. But I think I made the board compatible as I do not have a new Track side drawing and I just needed to add another link shown in purple.
Someone else had a problem getting his ESR meter working and sent it to me for repair which you can also do if you like. On that occasion it was a component mounted one hole out so it connected to the wrong track.
Just PM me and I will give you an address to send the board to if you would like me to get it going for you.
Les
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Old 21st Mar 2014, 11:21 am   #71
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Default Re: My Homebrew ESR Meter for testing el caps

hello Top Cap

thx for the tips and your layout which i used. I just realized that i got an 100mA meter instead of 100µA. Maybe the multimeter is just not able to measure that low. Also i will get new IC.
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Old 21st Mar 2014, 12:23 pm   #72
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Default Re: My Homebrew ESR Meter for testing el caps

If you're using Veroboard it's so easy to make a mistake. I had problems with mine but got it working after David, the OP helped me out. I made the stupid mistake of fitting the wrong resistor. Quite easy to do, mixing 100k for 100R, I wasn't taking care. Check, re check and check again your work with a magnifying glass.

This is a great little meter and well worth getting up and running.

Andy.
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Old 21st Mar 2014, 6:39 pm   #73
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Default Re: My Homebrew ESR Meter for testing el caps

This thread rumbles on, which I could never have envisaged when I started it off, but I haven't personally contributed to it since Jan 2011. I did however post a thread on the Golborne Vintage Radio Forum (where I'm known as 'Yorkie'). As on this forum, as the thread developed there are many posts and various other adaptations, and based on feedback from others I added additional features such as a reverse polarity protection diode for anyone wishing to power the unit from a 'wall wart' PSU, and I updated the PCB layout accordingly.

As a consequence, for anyone coming to it new and wishing to build the project it's next to impossible to know quite where to start. For this reason, to help potential new constructors to 'cut to the chase' Joe Freeman (moderator on the Golborne Forum - 'The Pillenwerfer' on this forum), kindly complied a document in PDF form with updates and amendments to the circuit and the PCB artwork for anyone wishing to make the PCB version. The PDF is too large to attach here but can be found at this link, which I hope might be of assistance to potential constructors:

http://golbornevintageradio.co.uk/fo...d.php?tid=1598

(There is no need to join the Golborne forum to access the PDF).

For anyone who builds the project in whatever form - be it on a PCB or strip-board - post #37 in this thread here might assist in troubleshooting if problems arise. In particular, if a scope is to hand the waveform patterns to be expected at the various points in the circuit as shown in post #37 should help locate any malfunctions. The oscillator that generates a square wave of 100kHz or thereabouts (actual frequency unimportant) is as simple as an oscillator could be, in that it comprises just one gate of the 74HC14 IC, plus R1 & C1 (which set the actual frequency). The first place to start troubleshooting is at pin 2 of IC1, where the 100 KHz square wave should be observed. If that square waveform isn't present, nothing else will work.

I would again reiterate and acknowledge that I claim no originality for this very useful little project - the original designer was Lawrence Glaister, Canadian Radio Amateur VE71T. I simply adapted his design to my own requirements and in the spirit of homebrew, shared that with others and developed the project further based on feedback I received.

I'm indebted to Joe Freeman for compiling the PDF, which I hope will prove helpful.
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Old 21st Mar 2014, 7:18 pm   #74
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Default Re: My Homebrew ESR Meter for testing el caps

It might be worth adding that in terms of sourcing components, the items that may not be in most constructors 'spares' boxes are the 74HC14 IC, 50uA meter, the 0.47UF 400V cap (C5) and the 2N222A transistor. They're all still available, reasonably priced, together with any of the other bits as might be needed, from (aptly named!) ESR Electronic Components as follows:

74HC14 IC: 18p:

http://www.esr.co.uk/components/products/frame-ics.htm

(The 'N' suffix if at the end of the 74HC14 IC simply denotes a 14-pin DIL package).

50uA meter, Order Code 124-116, £4.98

http://www.esr.co.uk/electronics/pro...test-panel.htm

470n 400V capacitor (C5) 22.5mm pitch leads – Order Code 848-069, 27p

http://www.esr.co.uk/components/prod...capacitors.htm

2N222A transistor: 23p:

http://www.esr.co.uk/components/prod...ransistors.htm

Plus £2.50 P&P plus VAT on total order.

I’ve no connection with ESR Electronics, except as a satisfied customer. I’ve found their prices and P&P reasonable, and their service - be it on the website or phone - excellent.
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Old 22nd Mar 2014, 10:37 am   #75
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Default Re: My Homebrew ESR Meter for testing el caps

It's a great little meter David, simple to make and adaptable; no wonder this thread is long lived.

A forum member popped over yesterday and I was showing him the meter I built, he went off with a 74HC14, so I guess another of your meters will be built soon.

Andy.
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Old 22nd Mar 2014, 8:53 pm   #76
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Default Re: My Homebrew ESR Meter for testing el caps

Yes, it's a useful little project Andy, especially for those who like to construct home-brew projects, as you and I do.

That said, I guess that to some extent these little multi-function Chinese jobbies which have appeared on the scene have rather put the mockers on it:

https://www.vintage-radio.net/forum/...d.php?t=104177
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Old 31st Jul 2014, 10:23 pm   #77
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Default Re: My Homebrew ESR Meter for testing el caps

Hello David. I have also built this nice little instrument. It works well, but the scale near the zero end is very crowded. The 1 Ohm point is only 1mm away from zero. The 10 Ohm is at 3/4 scale rather than half.
What should I modify to strech it out and increase the resolution.
btw, I'm using a 100uA meter, and 1k5 for R17.
Thank you.
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Old 1st Aug 2014, 10:16 am   #78
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Default Re: My Homebrew ESR Meter for testing el caps

Hi,

The reason that the scale is so cramped in your instance is that you're using a 100uA meter movement - not 50uA which is what was specified.

Though the scale isn't linear, it is expanded at the low Ohms (right hand) end of the scale. If you look at the excellent dial created by Colin at post #50 you will see that when using the specified 50uA meter, 2 Ohms is about 25% of the scale, 5 Ohms is 50% and 10 Ohms is 75%. Really, anything as high as 5 Ohms would be suspect and should be compared with a new cap of the same value. I've attached a table of ESR values showing the worst case (highest) ESR for caps of various values and working voltages, drawn up by Bob Parker.

I don't think there's anything you can do to expand the scale on the 100uA meter movement.

Frankly, the cheap little digital Chinese multi-testers which have come onto the market, which test caps including ESR, and resistors, inductors, transistors and diodes have rather eclipsed this useful little project in the four years since I posted the thread, but that said, here in the UK it can still be built for under £10GBP. The 50uA meter is still available for under £5.00GBP from ESR Electronics, but I don't know the situation in your country.

Sorry I can't be more helpful.

Vey best wishes.
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Old 9th Aug 2014, 3:27 pm   #79
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Default Re: My Homebrew ESR Meter for testing el caps

Hello again

I replaced now the parts and have now 74HC14 and 2N2222 in place but still get no output on the meter. The strange thing is that iI have 5v for a short time, then the 78L05 gets hot and the voltage drops, as if something was shorted.

Here are some pictures:
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Old 9th Aug 2014, 7:00 pm   #80
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Default Re: My Homebrew ESR Meter for testing el caps

Double-check those track cuts (did you miss any altogether?), and make sure there are no stray whiskers of solder between adjacent tracks (pins 10 and 11 of the IC?) and no solder bridges from leads on the topside through to the trackside.

I can also see a couple of solder joints that might be worth remaking for reliability's sake, though your problem is more likely to be caused by something making contact where it shouldn't than not making contact where it should.

Are all leads in the right holes? Is the polarity of the tantalum bead capacitor correct? Have any unused inputs on the IC been left floating? (It's CMOS -- high-frequency oscillation can increase current draw.)
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