question_answer

In a triode valve, the current in the plate circuit is controlled by

A)  ammeter                           

B)  grid

C)  cathode                             

D)  anode                

Correct Answer: B

Solution :

                 Triode valve consists of a long evacuated glass bulb. The bulb has three electrodes anode, cathode and grid (G). The grid controls the current in the plate circuit. When it is given a positive potential relative to the cathode, it helps the electrons in reaching the plate, so that more electrons reach the plate. Contrary to this when grid is given a negative potential it opposes the electron movement. Hence, grid is also called controlling device.