# Power Semiconductor Devices Solved Ex

A (BJT) emits a current of 1mA, and has emitter efficiency of 0.99. The base transport factor is 0.994 and a depletion layer recombination factor is 0.997. For the BJT calculate the following −

## The transport factor

The rewritten transport factor is given by −

$$\alpha =\gamma _{E}\times \alpha _{T}\times \delta _{r}$$

Substituting the values, we get

$$\alpha =0.99\times 0.994\times 0.997=0.981$$

## The current gain

Current gain is given by −

$$\beta =\frac{I_{C}}{I_{B}}=\frac{\alpha }{1-\alpha }$$

Substituting the values, we get

$$\beta =\frac{0.981}{1-0.981}=51.6$$

## The collector current

$$I_{C}=\alpha \times I_{E}=0.981\times 1=0.981mA$$

## The base current

$$I_{B}=I_{E}-I_{C}=1-0.981=19\mu A$$