Consider the transistor circuit below. Let p-50 and VA-40 a. (10 pts) Determine
ID: 2265739 • Letter: C
Question
Consider the transistor circuit below. Let p-50 and VA-40 a. (10 pts) Determine the value of RB nceded to set the emiter current to 2 mA 1· RC Q1 NPN RE 1K Answer b. (8 pts) Determine the voltage between the emitter and collector, V Ignore Va effects Answer c 8 pts) For the conditions in part (o), is the transistor in the saturation mode? Justify your answer. d (8 pts) Determine the resistance between collector and emitter, fo due to VA (3 pts) True or False. The transistor's QPoint for this type ofbas circuit is very sensitive to changes. e.Explanation / Answer
Answer:-a) By using kvl we can write for emitter to base part as-
0 - ((0.002/51)*RB) -0.7 - (0.002*1000) + 12 = 0
=> RB = 237.15 kOhm
b)Current Ic = 2*50/51 mA = 1.96 mA. So Vc = 0 - Ic*Rc = -5.88 V.
similarly VE - IE*RE + 12 = 0, VE = -10 V. Hence VcE = Vc - VE = 4.12 V.
c) For the BJT in saturation VCE = 0, but here this condition is not verified. So transistor is not in saturation mode.
d) Output resistance = VA/Ic = 40/1.96 kohm = 20.41 kOhm.
e) False. In this type of biasing Q-point is stable.