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previous: Joe Fuzz Hi, Jack. Nice to hear from you. ... -- 12/12/1999 9:46 PM

Re: Tube Driver Analysis Requested

12/12/1999 11:45 PM
AMZ	Re: Tube Driver Analysis Requested >>I thought that was your patent number. No, that's the patent number from Butler's original Tube Driver circuit. >>I thought that I_grid=0 for a tube which wouldn't allow any DC current to flow to the right. (As I understand it): Tubes aren't perfect devices and there is always some grid leakage. The tiny amount of current drawn across the signal grid resistor creates a positive voltage and secondary emission of electrons are attracted to the grid. Since the grid requires virtually zero current to perform its job, this space charge creates enough negative bias to allow the triode to operate. Since different tubes leak different amounts there may be a wide variation in performance from tube to tube in this circuit. regards, Jack

12/12/1999 11:45 PM

AMZ

Re: Tube Driver Analysis Requested

>>I thought that was your patent number.

No, that's the patent number from Butler's original Tube Driver circuit.

>>I *thought* that I_grid=0 for a tube which wouldn't allow any DC current to flow to the right.

(As I understand it): Tubes aren't perfect devices and there is always some grid leakage. The tiny amount of current drawn across the signal grid resistor creates a positive voltage and secondary emission of electrons are attracted to the grid. Since the grid requires virtually zero current to perform its job, this space charge creates enough negative bias to allow the triode to operate.

Since different tubes leak different amounts there may be a wide variation in performance from tube to tube in this circuit.

regards, Jack

Replies:

GFR Altough it's been patented, it's an... -- 12/13/1999 11:23 AM