Hmmmm¡.It seems to me that Vgc should be the RMS, NOT the peak value in determining the grid dissipation.? The RMS value will determine the actual amount of heating.? This makes the dissipation calculation better.? Additionally, duty cycle should also be considered.
where vgc is the peak positive grid to cathode voltage.
Ig is the DC grid current.?
grid dissipation is peak voltage multiplied by Grid current.?
If you run 100W CW exciter drive into an Eimac 3-500Z at the SB-1000 and AL-80B max limits listed in their manuals of Ig 200mA and Ip 550mA, then this is what calculates.?
as per Eimac data sheet, drive impedance is 115 and ?grid dissipation is 20W.?
2 figure out peak voltage:
?
if
voltage squared divided by resistance = power.?
?
then
100W CW drive X 115 drive impedance = 11,500. Extracting the sq root = 107.2V RMS.? for peak voltage, 107.2V x1.4 (2sq) = 150 peak voltage.?
finally
150 peak V multiplied by 0.2mA Ig = 30W grid dissipation. That exceeds Eimac listed grid dissipation by 50%.?
