Soak your eyes on this one:
Circuit values: 20uF at 400V, discharging through xenon horseshoe tube. Probe shorted to its ground lead, laying nearby on the bench.
The remarkable part is this is actually my analog scope. No storage involved, just a Tek 475. Or actually, as a friend put it, "storage camera ;)", since it was a 10 second exposure.
Tim
I like it! What's the V/div? Is it reproducable with a proper al-foil short? How about 50ohm terminated coax? How about no probe cable at all?
Dave.
oflash_Discharge1.jpg
So, you've made an air-core transformer with the ground lead/probe loop being the secondary.
I think it was 50mV/div (0.5V/div with the 10x probe), but since it's sensing uncalibrated current, that doesn't tell much.
The probe has to be pretty close to get a strong signal (I had it right over the capacitor), otherwise the probe picks up too much noise from the breadboarded(!) switching supply (a 400V, 30mA supply has to switch a lot of winding capacitance..).
Surprisingly, I got a similar pulse from a snap-in electrolytic. Those things are fast!
Tim
one:
I wonder what the probe would pick up from a camera's (xenon) flash nearby.
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