Where is the three-stage tube used
Triode is sometimes called a transistor, transistor, etc. It is a current control component, that is, the base current is used to control the collector current. Able to amplify weak signals into larger electrical signals, there are two types of PNP and NPN. It has three working states: cut-off state, amplified state, and saturated conduction. What we often use is the saturated conduction state. When in the saturated state, the transistor loses the current amplification effect, and the voltage between the collector C and the emitter E Very small, the Vce two-pole voltage is equivalent to zero, that is to say, the short-circuit state. This state is often used as a switch in conjunction with the cut-off state, especially in small-signal and small-current occasions.
The main function of the transistor is to amplify the current. Take the common emitter connection as an example (the signal is input from the base, output from the collector, and the emitter is grounded). When the base voltage UB has a slight change, the base current IB is also There will be a small change along with it. Under the control of the base current IB, the collector current IC will have a big change. The larger the base current IB, the greater the collector current IC, and vice versa, the smaller the base current. , The collector current is also smaller, that is, the base current controls the change of the collector current. But the change of the collector current is much larger than the change of the base current, which is the amplification effect of the triode. The ratio of the change in IC to the change in IB is called the magnification β of the triode (β=ΔIC/ΔIB, Δ represents the change.), the magnification β of the triode is generally tens to hundreds of times.
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