Sorry it is not a burst but a 5uS pulse at about 100 PPS.
By using long pulses like this I can use a simple diode rectifier and
single capacitor filter in the Plate current detector ckt.
73
Bill wa4lav
At 11:40 AM 12/9/2003 -0500, you wrote:
what sort of pulse width are you able to get?
working on ionospheric sounder for the back yard :-)
-bob
Bill Fuqua wrote:
Interesting item. By coincidence I am working on a power tube tester
today. I built one some time ago to check 4CX250B tubes because we go
thru a lot of them here. I built a pulse tester that basically applied
a large negative cut off voltage to the grid and then switched it to
zero for a few microseconds and measured the pulsed plate current. This
worked just fine but if the tube arced over I had to replace the hard to
find high voltage P channel MOSFETS. So, I have gone to a different grid
pulsing technique that uses a more common N channel MOSFET and is
transformer coupled to the control grid. It seems to work great even
with positive grid pulses over 2 amps. Now I can use it to check high mu
triodes as well. I have lots of RF power tubes at home and this way I
can test them with out having to have an amplifier. Even though the
plate current may be several amps the DC Plate supply only needs to be
good for a milliamp. or so.
I simply compare the results with the data sheets to see if the tube
is near spec.. This seems to work with in 10 or 15 percent using a new tube.
73
Bill wa4lav
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