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More SMPS Current transformer help (ramblings.)

Y

Yzordderex

Jan 1, 1970
0
In regards to the previous thread, I did some experimenting today.

Found a 25/15/10 toroid core in my toy box and wound 30 turns on it.
Measured 0.006H. Looks like 5860nH/T^2. Maybe 3E25 material.

I wound a 28t secondary and terminated with 30 ohms. I didn't have a
good current source to test, so connected the function generator to a
pair of 3904/3906 emitter followers in a totem-pole config and wired
em up to +-5v. Output of the totem-pole was driving 5 turns on the
primary in series with a 5ohm current viewing resistor. I drove this
set-up with about 600ma peak. Works out to a little more than 3v out.

With a 750Hz sinwave the signal was down 3db with a 45 degree shift.
At 5mHz the signal was still good. Shortly after 5mHz the driving
signal fell apart, but the output was following well. With a square
wave drive all looked good to 500kHz, then the driver fell apart
again.

Looks like this thing might work out, and I've got a few more of these
cores in my toy box. Hope to run through the calculations tonight to
verify flux density.

Thanks for help guys.

Stay Tuned - Next iteration will be near 10 amps sensed for my
Full Legal Limit 75 meter Amplitude Modulated Transmitter using a Zero
Voltage Switched Resonant Phase Shifted Full Bridge Switched Mode
Power Supply Modulator:)

73
Bob
N9NEO
 
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