The current gain of a common emitter amplifier is $69$ . If the emitter current is $7.0 \,mA$, collector current is :

Question

Consider the following statements A and B and identify the correct answer:

A. For a solar-cell, the I-V characteristics lies in the IV quadrant of the given graph.
B. In a reverse biased pn junction diode, the current measured in (µA), is due to majority charge carriers.

Answer 1

To solve the given problem, we need to find the collector current of the common emitter amplifier. We are provided with the current gain in a common emitter configuration and the emitter current.

The current gain in a common emitter configuration is defined as the ratio of the collector current (I_c) to the base current (I_b). The formula for current gain (\beta) is:

\beta = \frac{I_c}{I_b}

We can also express the emitter current (I_e) as:

I_e = I_c + I_b

From this, the base current (I_b) can be expressed as:

I_b = I_e - I_c

Substituting the value of I_b in the expression for \beta, we get:

\beta = \frac{I_c}{I_e - I_c}

Given that the current gain \beta = 69 and the emitter current I_e = 7.0 \, \text{mA}, we need to find the collector current (I_c).

Rearrange the above equation to solve for I_c:

\beta(I_e - I_c) = I_c

I_c = \frac{\beta \cdot I_e}{\beta + 1}

Substitute the given values:

I_c = \frac{69 \times 7.0}{69 + 1}

I_c = \frac{483}{70}

I_c = 6.9 \, \text{mA}

Thus, the collector current is 6.9 mA.

Therefore, the correct answer is 6.9 mA, and it matches with the provided correct answer.

Answer 2