THEORY OF THREE-ELECTRODE VACUUM TUBE CIRCUITS 531 



the equation (14) where coi/27r is equal to 250,000 and cu2/27r is equal 

 to 5,000,000 cycles per second. As a reference condition let us take 

 that for which the effect of the interelectrode capacitances is neg- 

 lected. The plate current for this condition is obtained from equation 

 (25) when Zi and Zz as well as Z2 are made infinite. As a next step 

 we compute the plate current from equation (24) when Zi, Z2, and Z3 

 are the impedances corresponding to the interelectrode capacitances 

 C\, C2, and C3, respectively. It is found that this plate current is 

 12 db below that obtained in the reference condition. Finally it is 

 of some interest to compute the plate current when the grid-plate 

 capacitance alone is effective. This plate current is obtained from 

 equation (24) by assuming Zi and Z3 to be infinite and Z2 to be the 

 impedance corresponding to the capacitance d. This current is 

 found to be 24 db below that of the reference condition. 



