[TenTec] Solid state amps

tongaloa tongaloa at alltel.net
Tue Dec 9 11:40:18 EST 2003


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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