Video Solutions for GATE 2002 ECE : Five Mark Questions (Electron Devices)

1. Each transistor in figure, has a dc current gain β_dc = 50, 

cut in voltage V_γ = 0.65 volts and V_BEsat = 0.75 volts. 

The output voltage V_o for T₂ in saturation can be as high as

0.2 volts. Assume 0.7 volts drop across a conducting PN junction. 

  Determine

              (a)  The minimum value I_B2 necessary to keep T₂   

                     saturation.

              (b)  The maximum permissible value for the resistance 

                     R_B1.

              (c)  The worst case high input (logic 1) and the worst case 

                     low input (logic 0) for which T₂ will be either in 

                     saturation or in cut off.