Answer to Question #123939 in Electricity and Magnetism for sami

Question

The collector current of a transistor used as an amplifier changes from 6MA to 18MA as the base current change from 5µA to 25µA. What is the current amplification factor of a transistor?

Answer 1

By definition, the current amplification factor of a transistor is:

$$\beta = \dfrac{\Delta I_{coll}}{\Delta I_{base}}$$

where $\Delta I_{coll}$ is change in the collector current when the base current changes by $\Delta I_{base}$.

Substituting values, get:

$$\beta = \dfrac{(18-6)\cdot 10^{-3}A}{(25-5)\cdot 10^{-6}A} = 600$$

Answer. The current amplification factor of a transistor is 600.