[Amps] grid fuses

[Will Matney]

Rich,

How can it collect electrons from the cathode and take a charge when the path back to the cathode is broken via a blown fuse between the grid and ground making an open circuit? That would be like a capacitor charging up with only one lead connected to a power supply, and the other lead left un-connected. It can do it before the fuse blows, but not afterwards, there's just no path for it to work. To me, without the connection to ground (an open grid circuit), the electrons will go by the grid, some even striking it, but there's no circuit for any of them to do anything. I would think in order for the grid to take any charge, there would have to be a circuit back to the cathode for the electrons to complete the circuit. The triode with an open grid would then virtually be a diode in operation without the grid connected. If the grid could take a charge and it open, one could kill the power on the tube, connect a meter between the open grid and ground, and see the grid discharge through the meter just like watching a capacitor discharge. I've never seen that in my life, nor ever seen a capacitor take a charge just from one lead being connected to a current source.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 7/20/06 at 9:47 PM R L Measures wrote:

>On Jul 20, 2006, at 4:48 PM, Will Matney wrote:
>
>> Tom,
>>
>> The problem is, you stated all this can occur after the fuse or  
>> resistor opens. It can not, only before it does.
>>
>> "Now when the tube faults and if the resitor opens, the grid can  
>> rise to full anode voltage"
>>
>> If the grid doesn't make a connection to anything, it can't conduct  
>> and hurt one thing, it's just there in space.
>
>... collecting a negative charge from electrons emitting from the  
>cathode.
>
>Free, unsolicited advice for young debaters:  When you don't know,  
>opening your mouth not advisable.
>
>>
>
>R L MEASURES, AG6K. 805-386-3734
>r at somis.org