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previous: Stephen Conner R.G.,You obviously ... -- 9/23/1999 4:08 PM

Re: death by cherrying?

9/23/1999 4:38 PM
kg	Re: death by cherrying? I dunno for sure, Steve, but I _think_ the max cathode current is a steady-state DC condition. Otherwise most of the tubes I use and abuse wouldn't last longer than a few days at most. You have the concept of the space charge to contend with as well, which is nothing more than a cloud of liberated electrons emitted from the cathode and held in place by the negative charge of the grid. This acts as a kind of reservoir which can supply peak current higher than the cathode could emit on its own. Trouble is, equations that I've seen for the space charge lead one to believe that it could be exhausted in a matter of milliseconds, which isn't really long enough to supply some of those peak currents. Ken

9/23/1999 4:38 PM

Re: death by cherrying?

I dunno for sure, Steve, but I _think_ the max cathode current is a steady-state DC condition. Otherwise most of the tubes I use and abuse wouldn't last longer than a few days at most.

You have the concept of the space charge to contend with as well, which is nothing more than a cloud of liberated electrons emitted from the cathode and held in place by the negative charge of the grid. This acts as a kind of reservoir which can supply peak current higher than the cathode could emit on its own.

Trouble is, equations that I've seen for the space charge lead one to believe that it could be exhausted in a matter of milliseconds, which isn't really long enough to supply some of those peak currents.

Ken