61. Obtain the collector voltage, for the collector resistor (RC. = 5.6kΩ, IE = 1.664 mA, and VCC = 10v for single input unbalanced output differential amplifier
A. 0.987v
B. 0.682v
C. 0.555v
D. None of the mentioned
Answer: B
Substitute the given values in the collector voltage equation,
VC = VCC – RC × IC
⇒ VC = 10v – 5.6kΩ × 1.664 mA (∵ IC ≅ IE )
⇒ VC = 0.682v.
62. For the circuit shown below, determine the Output voltage (Assume β = 5, differential input resistance = 12 kΩ)
A. 4.33v
B. 2.33v
C. 3.33v
D. 1.33v
Answer: C
From the circuit dig, RC = 10kΩ, Vin1 = 1.3v and Vin2 = 0.5v,
Differential input resistance = 2 βre,
⇒ 12kΩ = 2 × 5 × Re
⇒ Re = 1.2 kΩ
Output voltage Vo = RC/2Re(Vin1-Vin2)
⇒ Vo = 10kΩ/(2 × 1.2kΩ) × (1.3v-0.5v)
⇒ Vo = 3.33v.
63. In a Single Input Balanced Output Differential amplifier, given VCC = 15v, RE = 3.9kΩ, VCE = 2.4 v and re = 250Ω. Determine Voltage gain
