Introduction of triode

Triode, in the Chinese meaning, is just a general term for three-pin amplifier devices. The triode we often talk about may be several devices.

It can be seen that although they are all called triodes, in fact, the terms in English are very different. The term triode is actually a unique Chinese vocabulary in the pictographic sense.

"Triode" is the English translation of "Triode" in the English-Chinese dictionary. It is related to the first appearance of the electronic triode. It is the thing that the word triode refers to at the beginning. The rest of the devices called triodes in Chinese cannot be translated into Triode in actual translation.

Product function

The transistor has a current amplifying effect, and its essence is that the transistor can control a large change in the collector current with a small change in the base current. This is the basic and important characteristic of the triode. We call the ratio of ΔIc/ΔIb the current amplification factor of the transistor, which is represented by the symbol "β". The current amplification factor is a fixed value for a certain triode, but it will also change with the change of the base current when the triode is working.

Working status

Deadline

 When the voltage applied to the emitter junction of the transistor is less than the conduction voltage of the PN junction, the base current is zero, the collector current and the emitter current are both zero, and the transistor loses the current amplification effect at this time, and the collector and emitter are equivalent. In the off state of the switch, we call the triode in the off state.

Magnified state

When the voltage applied to the emitter junction of the transistor is greater than the turn-on voltage of the PN junction and is at an appropriate value, the emitter junction of the transistor is forward biased, and the collector junction is reverse biased. At this time, the base current is opposite to the collector. The current plays a control role, so that the transistor has a current amplification effect, and its current amplification factor β=ΔIc/ΔIb, and the transistor is in an amplified state.

Saturated conduction

When the voltage applied to the emitter junction of the transistor is greater than the conduction voltage of the PN junction, and when the base current increases to a certain extent, the collector current no longer increases with the increase of the base current, but at a certain level There is not much change around the value. At this time, the triode loses its current amplification effect, the voltage between the collector and the emitter is very small, and the collector and emitter are equivalent to the on-state of the switch. This state of the triode is called the saturated conduction state.

According to the potential of each electrode when the triode is working, the working state of the triode can be judged. Therefore, electronic maintenance personnel often use a multimeter to measure the voltage of each pin of the triode during the maintenance process to determine the working condition and working state of the triode.

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