What is the working principle of PNP transistor and the operating voltage and current of the switching function?

1.PNP Tube Amplification Principle:

When the vc<vb<ve of the PNP tube, so that the collector junction reverse bias, the transmitting junction is biased, the emitter current of the tube flows into the pipe, the base current and the collector current flow out of the pipe, and the collector current and the base current between the beta relationship, the three-pole current to meet the Ie=ib +ic=ib (1+β IB). That is, the base current can control the collector current, which is called the amplification effect of the tube.



2. Switch action principle:

when the pipe vc>vb, and Ve>vb, the collector junction and the transmission junction are biased, the pipe work in saturation, at this time the pipe pressure drop is about 0.1-0.3v. IC=VCC/RC, that is, the collector current depends largely on the collector power and the collector resistor, independent of IB, equivalent to a closed switch.



when Vc<vb Ve<vb, the two PN junctions are reversed and the pipe works in the cut-off state. At this time, the three electrodes of the tube have no current. Equivalent to a disconnected switch.



3.

IC=VCC/RC Tube pressure drop when current and voltage values are saturated  | uce|=0.1-0.3v  VC is about equal to ve are greater than vb,| VBE|=0.3V (Germanium tube) or 0.6V (silicon tube)



at the end of the IB, IC, ie are approximately 0. (Micro-safety penetration current, very small)