Massive oscillation issues with the SHO

kristoffereide · July 20, 2009, 03:23:42 PM

I decided to try this SHO everyone's been talking about, but I get little or no drive and massive oscillation.
I've used the exact parts from renegadrians layout.

Are my mosfets bad?

Ripthorn · July 20, 2009, 03:35:38 PM

Did you make the correct track cuts? Is the transistor in the right way? It's such a simple circuit that the problem is also most likely very simple.

kristoffereide · July 20, 2009, 03:38:45 PM

yes I've checked several times, so unless the transistor is the wrong way in the layout everything is as it should be...

frokost · July 20, 2009, 03:53:05 PM

Never trust a layout. Trust the datasheet.

kristoffereide · July 21, 2009, 06:09:14 AM

ok... Where can I find the datasheet for my exact mosfets? The seller did not provide me with manufacturers name. Bought from Banzai, but not the Zetex ones

The only info is N-VMOS 60V 0,5A 0,83W 5R TO92

frokost · July 21, 2009, 06:21:11 AM

Google. "BS170 datasheet" should get you there. Seems like the layout is correct. Time for "DEBUGGING - what to do etc".

kristoffereide · July 21, 2009, 06:24:58 AM

yes it's that time again... I just made a long shot hoping someone had the same problem thus knowing how to fix it

frokost · July 21, 2009, 06:27:55 AM

Hehe. I actually follow that procedure even when I don't intend to post here. Just following the steps helps you locate and fix the problem yourself. I think that's fairly common.

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Massive oscillation issues with the SHO