As long as there is a small base current, the triode will have a large collector current and emitter current, which is determined by the characteristics of the triode. The current magnification of different transistors is different, so the amplification ability of different transistors to base current is also different.

Base current is signal input current, collector current and emitter current are signal output current, and signal output current is much larger than signal input current, which shows that triode can amplify input current. In all kinds of amplification circuits, this characteristic of triode is used to amplify signals.

When triode works normally, its base current, collector current and emitter current exist at the same time and disappear at the same time.

Extended data

1. Transistor is a current amplifier with three poles, which are called collector C, base B and emitter E respectively. Divided into NPN and PNP.

2. When the triode is used in the actual amplification circuit, an appropriate bias circuit is needed. There are several reasons for this. Firstly, due to the nonlinearity of transistor BE junction (equivalent to a diode), the base current can only be generated after the input voltage reaches a certain level (usually 0.7V for silicon tubes). When the voltage between the base and emitter is less than 0.7V, the base current can be considered as 0.

3. Different connection modes of triode have different characteristic curves. * * * emitter circuit is the most widely used, and the characteristic curve of * * * emitter can be drawn by tracing point method or directly displayed by transistor characteristic plotter.

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