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Registered Member #195
Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111
the whole circuit might be feeding back on its self. add some tantalum to the chips close to the IC power pins. also the correct ferrite core will help. if you are energetic use a proto board with a ground plane. some times those chips have problems driving transformers if it is not done right.
Registered Member #7222
Joined: Sat Oct 13 2012, 06:04AM
Location:
Posts: 18
Hi Guys, I'll try everything above :P
I've added a .1 uf cap too the primary of the GDT helped a bit . The signal is sooo bad my cro can't even trigger correctly :/ to show me the waveform. I believe i'm getting feedback issues. I've added a small 100uf cap to the output of the 5v regulator as it was struggling to supply enough current to the 74hc14.
Ash I have an ferrite core from a ATX power supply ? Is this suitable ? and if so what is the best way to go about utilising it.
Teravolt To confirm i'm adding the tantalums to the VCC of the chips then to ground ? Is the the parrallel 10 ohm and series 1uf on the primary or secondary side of the GDT ?
If all else fails i'm making a PCB in eagle :D Thanks :P
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Jazzman56 wrote ...
Ash I have an ferrite core from a ATX power supply ? Is this suitable ? and if so what is the best way to go about utilising it.
If it's a toroidal one and it's yellow/white or something like that I think it's iron powder, and therefore not suitable.
If it's an 'EE' core, it should be usable. They do say you get better coupling (less losses) with a toroid, but other forms of core should still be ok.
Registered Member #4603
Joined: Wed Apr 25 2012, 07:33PM
Location: Austria
Posts: 159
Hi. I have a question about cat5 cables and GDTs. I don´t want to open a new thread for only a short question so i hope it is OK to post it here.
Can i also use a shielded cat5 cable e.g. cat5e to wind a GDT or will it be counterproductive? I got some cat5 cable in an electronic store and i did not notice that it was a cat5e cable... I already wound 2 GDTs with it...
Registered Member #7222
Joined: Sat Oct 13 2012, 06:04AM
Location:
Posts: 18
Hi Rate Reducer,
I'm pretty sure it is ok to use Cat5 cable to wind GDT's i didn't have any on hand so i use some hookup wire (essentially the same thing but with a larger insulation layer). I'm not sure on shielded wire though.... i though you could get pretty similar results by just twisting individual pairs together.
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GDT HELP
