Analysis of Inverted State of Transistor

Analysis of Inverted State of Transistor

What is the inverted state of a transistor?

The collector junction is forward biased and the emitter junction is reverse biased, in an inverted state. The collector junction bias and emitter junction bias are already saturated. The collector junction is reverse biased, and the emitter junction is reverse biased, in a reverse cutoff state. The collector junction is reverse biased, and the emitter junction is forward biased, in an amplifying state.

2. Analysis of Inverted State of Transistor

In fact, when the potential relationship between the three electrodes of an NPN transistor is UE>; UB>； At UC, the states of the two PN junctions in the transistor are reverse bias of the BE junction and forward bias of the BC junction.

3. Understanding of reverse amplification of ternary diodes

(1) When a transistor operates in reverse phase, it is equivalent to switching between the emitter and collector (i.e. the collector acts as the emitter and the emitter acts as the collector), and there are also three working states for a transistor in reverse phase. However, the ratio of equivalent collector current (IE) to base current, denoted as β, is much smaller than when the transistor is directly connected. Therefore, the base driving current required to enter the saturation region of the inverting transistor is much larger than when the transistor is directly connected, but the voltage drop of the transistor is smaller than when it is directly connected.

4. Application of tripod diode in inverted state

① A multi emitter transistor used as a signal input in TTL digital integrated circuits, which is an inverting transistor when the input is at a high level of 1. When a transistor is used in an inverted state, the bias of its two PN junctions is opposite to that when operating in an amplifying state: the emitter junction is reverse biased, and the collector junction is forward biased. Therefore, the collector junction may burn out and the emitter junction may break down. However, due to the small voltage amplification factor β of the transistor operating in the reverse phase state, such as the β value of the planar transistor being around 0.1~0.5 when used in the reverse phase state, it will not burn out. Currently, it is rare to use trialkenes as the inversion state.

② When using a digital multimeter for detection, analysis, and judgment of the three different electrodes of a transistor, the "three inversion" method can be used simultaneously to find the base and determine the transistor type, while the determination of the collector and emitter requires the inverted social state of the electronic transistor. Taking the NPN transistor as an example, the multimeter mainly selects the R × 100 or R × 1K range for learning the ohm range. According to Figure 1, pinch the base and unknown electrode of the transistor with your fingers, connect the black probe of the multimeter to the unknown electrode Y, and connect the red probe to the X, and observe the pointer deflection at a certain angle. Connect the data as shown in Figure 2 and observe the deflection angle of the pointer. Comparing two important pointer deflection angles, the one with the larger deflection has the black probe connected to the collector. The two system wiring design methods for this situation correspond to the two development states of the transistor: the amplified living state and the inverted cultivation state. The time when the pointer deflection was not small, the black probe (with the DC motor power supply as the positive pole in the multimeter) was connected to the emitter of the transistor. At this point, the transistor is divided into three representative electrodes with a potential relationship of UE>UB>UC. The transistor is controlled to operate in an inverted state, and the current through which the multimeter pointer deflects is the emitter current. Because the current changes slightly during this process, the degree of pointer deflection is relatively small. Another wiring operation corresponds to the amplification technology state of the transistor, which achieves a higher economic current density by using the current of the pointer as the collector output current, corresponding to a larger pointer deflection of the multimeter.