Transistor, also referred to as a bipolar junction transistor, the equivalent of two back-to-back diode PN junction. Forward bias EB knot holes injected from the emitter region, during which most of the boundary of the hole to reach the collector and CB in reverse bias junction barrier under the action of electric field reach the collector region, form the collector current IC. In the common-emitter transistor circuit, launches in the base circuit is racing to bias the voltage drop is very small.
500 ω collector there is a voltage drop across the load resistance VRC=10mA*500 ω =5V, transistor voltage drop between collector and emitter for VCE=5V, if an alternating base stacking in the bias circuit for small current IB, appears in the collector circuit a corresponding alternating current IC, c/IB= beta, bipolar transistor's current amplification is realized.
Most of the collector bias voltage between the emitter and is added on the reverse biased collector. Since VBE is very small, so the base current is approximately IB=5V/50k ω =0.1mA. If the transistor's emitter current amplifying coefficient β =IC/IB=100, collector current IC= beta *IB=10mA.