Universal coil tester

[6666]

Hi Maurice
any chance you could do a print screen from diptrace so we can see your coilset cct?
thanks

[MAURICE]

6666
With pleasure in fact diptrace can save as JPEG ( very useful ) I just haven't used that feature but will do so in the future.
A lot of the circuitry is not needed but I have put it in because I am a little new to detectors and didn't want to leave out something and later regret it.Using info from tgsl101 pdf by Don Bowers I think this circuit maybe useful.
Please note it has IGSLMC OSCILLATOR with altered values. As I am building IGSLMC.
best regards
MAURICE

[6666]

MAURICE
thanks for the jpg, that's a good feature
very handy schematic.

[ONoff]

R3 = 47 kOhm or 470 kOhm?

[zomby]

470к

[ONoff]

470ê

thank you!

[bernte_one]

hello maurice

can you make a little pcb layout as black white image for your shematice
and too a component overlay.
or can you upload some pcb files.

it is not the complete tgsl circuit right?
onkly a part too test coils?

would be nice to hav a coil tester.

regards

[satdaveuk]

universal coil tester

Hi
This thread is based apon the universal coil tester not coil testers thats only good for a particular project ie Maurice circuit based arround the ITGSL.
The project that I put on here covers all makes and types of detectors and alot more equipment that can run into the GHZ.
Ive built a few coils now with it the last been for the whites 1V which included the final nulling turned out yet another success.
If you cant get on with the simple build put on here you must be missing something, maybe I didnt explain myself properly or maybe its me thats missing something else your after

Regards

[bernte_one]

hello dave

thanks for reply
i will take a look at your documets for universal coil tester
i have a multimeter, rcl meter and usb oszi is this enough and soon your coil tester
did i need something else or is that all i need to test coils

until here thanks for this project

regards

[reiv]

Hi I have made this coil tester too, to build another White`s IDX coils. With Tx is working ok and I get 6.5kHz, but with Rx there is no reaction.. Rx data: 0.2 wire 372turns at 120mm diameter.

[satdaveuk]

Did you check each component for spec before placement?
If your answer is a no then resistors should be 1%, you have used 5%, two of which are in series so that could be another 10% out, Caps look fine but if not checked for accurate value they could be miles out.
The transistor Bc327 you fitted, for the sake of £1 or less fit the 2n2907 metal case, its made for the job.
Last but not least get it into a small metal housing to screen it from all outside sources making socket connections with screened lead.
Golden rule= with 99.9% of proven projects on Geotech,( build to spec and you get success) If you go down the other road you will be scratching your hair out and end up with a third rate build.
Regards to all
I miss this forum
Not been on here for a few month due to work load, its gone crazy.
Dave

[reiv]

Thanks for replay Dave. I measured all components before turns on. It loks like this: R1-55.4Ohm, R2-463Ohm, R3-472kOhm, R4-469Ohm, C1-44nF, C2,C3-47pF, C4-100,8uF/16v, C5-45nF,TR1-BC237(another, in my country hard to find 2N2907), FT1,FT2-BF245B. Like I said earlier with Tx coil works fine sinus 6.5kHz, But with Rx no respond. I think this circut can`t oscillate with that kind of coil (36mH), soe I give up. I have build another simple circut:

[satdaveuk]

What frequency should the RX coil oscillate at? The reason why I ask is because the frequencies we are are dealing with in general with MDs is low,which takes us to very basics of oscillators which I was building when still at school 40 years ago, so there shouldnt be a problem if using the correct components on your build.
All I can further tell you is, its a well proven design which has been kicking around for years and used for all sorts of coils hence the name universal.
At a guess I think your main problem is the 2n2907 substitute you have used.
I bet some of the boys on here are knocking one of these together now, just to prove a point lol

Regards

[reiv]

L=35.6mH, C=33nF, soe it should be abut 4.6kHz. I have made some simulations and this are the results:


another oscillator:

[satdaveuk]

With R1 Been 56ohms and yours read 55.4ohms and should be 56k, im surprised it oscillated at all, and no wonder you got all the spikes in your simulation because you have shunted the base almost to deck.
If you look I specified R1= 56kohms which is 56,000 ohms.
I advise you check the other components because its getting late now, but if there ok just substitute R1 to correct value and all should work ok, although I would try getting yourself a 2n2907 because the specs are different as in the 2n2907 application is high speed switching where as the BC337 is general purpose aLso collector base capcitance is 8pf where as yours is 18pf also the 2n2907 frequency is 200mhz where as yours is 60mhz, not that it wont work its just maybe you will suffer with performance when judging it against the build that I posted here.
You live and learn, just keep in mind in the fucture to check and double check component values, not just by what they say on the packet or there markings because its a jungle out there.
When finely installing the components after weeding out the crap, always work with PCB layout and circuit diagram and parts list hand in hand, and marry the three up as you go along.
So its circuit number-part no- value.
By doing it that way your giving yourself a double check on values, making sure your PCB print is working along the same lines as your circuit diagram.
If everything lines up and the design was ok, then it will work.
Regards