From: Paul
Date: Sat, 03 Feb 2001 22:40:36 +0000
Subject: Re: [TSSP] 50 ohm Generator hookup
Terrell W. Fritz wrote: > I have my small coil. It is about 1180 turns #24 on a 4.25 inch form > 26.125 inches long. Only a little shorter than your big coil. Too small and its very sensitive to probe capacitances, too large and it becomes a major exercise to surround it with a screen. Maybe 12 to 14" might be about right. > http://hot-streamer.com/temp/box.jpg > http://hot-streamer.com/temp/box2.jpg Looks like just the job. > The ferrite transformer is 10 litz turns on the secondary. I sort of lost > track of the turns on the primary but I don't think that matters. Not at all critical, main thing is the windings don't flap about so its stable. > You had the ground of the input isolated in the drawing. I didn't > have any isolated BNC connectors but maybe that does not matter? Yes, I should really have shown the drive connection shield grounded. > The signal generator's output is floating > given some capacitance to ground. I'll test it out as see how it works. I think you'll find it'll make for more stable, repeatable measurements. You can use it in various ways. For eg you can feed the drive in across the Rs, ie through the 'current' port, and use the xformer as a CT, to take a current sample out the 'drive' port. Length of coax connected to the 'volts' port should be kept to 3 m or less, because it's shunt capacitance steals some of the measured current, but for a known length its C can be allowed for. Cheers, -- Paul Nicholson, Manchester, UK. --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.