EC-transistor quiz1

If the emitter resistance in a common-emitter voltage amplifier is not bypassed, it will

• reduce both the voltage gain and input impedance

• reduce the voltage gain and increase the input impedance

• increase the voltage gain and increase the input impedance

• increase the voltage gain and reduce the input impedance

In the circuit shown, the PNP transistor has |VBE|=0.7V and β = 50. Assume that R_B = 100 kΩ. For V₀ to be 5 V, the value of R_C ( in kΩ) is _____________.

• 1KΩ

• 2KΩ

• 1.5KΩ

• 1.8KΩ

A cascade connection of two voltage amplifiers A1 and A2 is shown in the figure. The open-loop gain A_v0, input resistance R_in, and output resistance R₀ for A1 and A2 are as follows:
A1: A_v0 = 10,R_in = 10 kΩ ,R₀ =1 kΩ
A2 : A_v0 = 5,R_in = 5 kΩ , R₀ = 200 Ω
The approximate overall voltage gain Vout/Vin is ______.

• 44

• 34.7

• 15

• 54

In the circuit shown below, capacitors C₁ and C₂ are very large and are shorts at the input frequency. V_i is a small signal input. The gain magnitude |V0Vi| at 10 Mrad/s is

• maximum

• minimum

• unity

• zero

The amplifier circuit shown below uses a silicon transistor. The capacitors C_C and C_E can be assumed to be short at signal frequency and the effect of output resistance r₀ can be ignored. If C_E is disconnected from the circuit, which one of the following statements is TRUE?

• The input resistance increases and the magnitude of the voltage gain Av decreases

• The input resistance decreases and the magnitude of the voltage gain Av decreases

• The input resistance decreases and the magnitude of the voltage gain Av increases

• The input resistance increases and the magnitude of the voltage gain Av increases

The cascode amplifier is a multistage configuration of

• CC-CB

• CB-CE

• CE-CB

• CE-CC

Assuming V_Cesat=0.2V and β = 50, the minimum base current (I_B) required to drive the transistor in the figure to saturation is

• 0.056 mA

• 26mA

• 0.045mA

• 0.08mA

Introducing a resistor in the emitter of a common amplifier, stabilizes the dc operating point against variations in

• temperature

• beta

• temperature and current gain

• none of the above

A BJT is said to be operating in the saturation region if

• both the junctions are reverse biased

• base emitter junction reverse biased and collector base junction forward biased

• base emitter junction forward biased and collector base junction reverse biased

• both the junctions are forward biased

In the circuit shown,the silicon BJT has beta=50,Vbe=0.7v,Vce(sat)=0.2v,which one of the following statement is correct?

• For Rc=1kiloohm,BJT operates in saturation region

• For Rc=3 kiloohm,BJT operates in saturation region

• For Rc=20 kiloohm,BJT operates in cut off region

• For Rc=1kiloohm,BJT operates in linear region