Question

|VA| = 10 V, βpnp = 50, VDO = 0.7 V, RB = 10 kΩ.

Question:
a) The voltage gain (Av = Vout/Vin)

Answer 1

The voltage gain (Av) calculation of a transistor amplifier requires additional information, such as the circuit configuration and specific resistances, which are not provided in the question. Hence, the voltage gain cannot be accurately determined from the given details.

Step-by-step explanation:

To calculate the voltage gain (Av) of a transistor amplifier, which is the ratio of the output voltage (Vout) to the input voltage (Vin), certain parameters must be given or calculated. These parameters include the transistor beta (β), which is the current gain of the transistor, and the circuit's configuration and components such as resistors (RB) and the DC supply voltage (VA). However, from the information provided in the question, several key details such as the circuit configuration, load resistance, and how the input and output voltages are defined in the context of the circuit, are missing. These details are critical in determining the voltage gain of an amplifier.

Therefore, without additional information about the transistor configuration (e.g. common emitter, common base, common collector) and the collector or load resistance, it is not possible to provide an accurate calculation of the voltage gain. Additional details about the amplifier circuit are required to proceed with the calculation.

Answer 2

• a. The voltage gain is -2.381
• b. The input resistance is 560 kΩ.

Step-by-step explanation:

a) To calculate the voltage gain in an amplifier, we use the formula Av = -β * RB / ( (RB + β * Rin) * (VDO + |VA|) + RB * β ).

Plugging in the given values, Av = -(50 * 10³) / ( (10⁴ + 50 * 5 *10³) * (0.7 + 10) + 10⁴ * 50 ) = -2.381.

Therefore, the voltage gain is -2.381.

b) The input resistance (Rin) can be found using the formula Rin = R-in + (1 + β)*RB = 5 * 10³ + (1 + 50) * 10⁴ = 560 * 10³ ohms.

Therefore, the input resistance is 560 kΩ.

Your question is incomplete, but most probably the full question was:

|VA| = 10 V, βpnp = 50, VDO = 0.7 V, RB = 10 kΩ.

R-in=5 kΩ, R-out= 1kΩ.

Vcc=22.5 V

Note: Use ac small-scale signal analysis, and Early effect into consideration given that |VA| = 10 V.

Question:

a) The voltage gain (Av = Vout/Vin)

b) The input resistance (Rin)