V B B can vary between 0 and 5 V . Find the minimum value of base current and V B B , so that transistor works in saturation mode. [Given β = 200 and V BE = 1 V ]

Step-by-step solution

When switched on, V C E = 0 V C C - R C i C = 0 i c = V C C R C = 5 1 × 10 3 = 5 × 10 - 3 A i c = β i B i B = i C β = 5 × 10 - 3 200 = 2 .5 × 10 - 6 A = 2.5 μA Using KVL at input side, V B B - i B R B - V B E = 0 V B B = V B E + i B R B = 1 + 100 × 10 3 × 25 × 10 - 6 = 1 + 2.5 = 3.5 V