Looks quite good, actually. Like Fred says, integrate, then you will have
it right.
Try amorphous or nanocrystalline cores, too. They switch quite quickly.
I've built a toy circuit that generated enough harmonics to cause itself to
ring a bit; the risetime was under 1us.
Physics guys use the stuff to generate fast (1us) current pulses for
particle accelerators and junk. They drive them with 3kA+ IGBTs, which
don't even switch as fast (~1us). Lots of power density.
Tim
--
Deep Friar: a very philosophical monk.
Website:
http://webpages.charter.net/dawill/tmoranwms
"Robert Baer" wrote in message
net...
OK, i decided to have a little fun messing with computer cores from
the IBM 1620 etc.
Had 3 sizes to look at:
Large: 0.135 OD, ~0.072 ID, 0.071 thick (used 10T primary, 1T
secondary) [possibly could do 50T]
Medium: 0.070 OD, ~0.045 ID, 0.024 thick (used 5T) [possibly could do 20T]
Small: 0.050 OD, 0.029 ID, 0.011 thick (used 3T) [possibly could do
5T, guess absolute max 7T]
Used #36 wire as that was all i had in small (thermaleze) wire.
Started with the large core, HP3312 function generator set to sine
drive 10V pk-pk driving in series 50 ohm resistor then primary of core
to ground; Tek P6019 probe for monitoring current drive and standard
probes to monitor voltage at top of primary (and secondary in this case).
Gee aren't transformers nice?
Secondary was essentially one-tenth the amplitude of the primary at
any reasonable frequency.
So i dumped the use of a secondary for monitoring amplitude/waveshape.
Basically, "BH" loop not seen; only a nice ellipse - BUT spikes on
the end: right side positive and left side negative.
"Interesting" part was the secondary showed opposite polarity on the
spikes.
Spikes increased in amplitude with drive and/or frequency.
So, i switched from XY mode to time domain; see Large.gif attached;
65Hz drive 10mV/div vertically.
Notice the spikes are a bit after the cross-over.
Basically the same thing seen with the medium-sized core; 600Hz
drive; notice spikes a lot smaller.
Did not bother taking a pic of what i saw when trying the small core.
Spikes were very dinky, hard to find/see but consistent in
positioning and amplitude at any reasonable frequency.
So..nothing like a BH loop and spikes (??) instead, consistent in
positioning on drive waveform.
Any hints, comments or suggestions?