乜野係forward biasing in transistor?

forward bias
A PN junction bias which allows current to flow through the junction. Forward bias decreases the resistance of the depletion layer. As a result, a large current flow through the transistor. (The transistor is working as amplifing the base current).
reverse bias
Bias on a PN junction that allows only leakage current (minority carriers) to flow, such that little or no current flows. Positive polarity on the n-type material and negative polarity to the p-type material.

transistor向前走，transistor向後走