​how to detect a bandstop transistor?

how to detect a bandstop transistor?

Because of the internal resistance,the high resistance gear should be measured during testing.The method of distinguishing electrode can be based on

The structure is distinguished by ordinary tube.

What is a photosensitive transistor?

Photosensitive transistor can realize photoelectric conversion and amplification function,so it is widely used in light controlled electricity.

The symbol of the photosensitive transistor is VT,which has two types of common type and compound type.According to the type of conduction,it is divided into two types,NPN and PNP photosensitive transistors.The graphic symbols are shown in Figure 6-6.Its base is the light window,so it has only the emitter E and the collector C two pins,near the tube key or color point is the emitter E (long foot),the other is the collector C (short foot);a few photosensitive transistor base B has pins,used as temperature compensation. At present,the structure of silicon photosensitive transistor is shown in Figure.

The base of the photosensitive transistor is equivalent to a photodiode with the PN junction between the collector,and the photocurrent produced in the light is amplified from the base to the human body tube,so the photosensitive transistor output can reach the beta times of the photosensitive diode.

The main parameters of the photosensitive transistor are as follows.

when the maximum operating voltage is VcEo without light,the maximum operating voltage allowed by the photosensitive transistor is generally at 10~50V when the leakage current between the E and C poles is not more than the specified value (about 0.5 A).

dark current ID dark current is the leakage current between E and C poles of photosensitive transistors in the absence of light,usually less than 1 A.

photocurrent Ir photocurrent refers to the collector current of photosensitive transistors usually up to a few milli ampere when subjected to a certain illumination.

the maximum permissible power consumption PcM maximum allowable power consumption refers to the maximum power consumption of photosensitive transistors without damage.