Main parameters of transistor 1

The parameters of a transistor can be divided into DC parameters, AC parameters, limit parameters, and characteristic frequency. The parameters of a transistor are an important basis for the use and selection of a third stage transistor. Therefore, understanding the parameters of a transistor can avoid damage to the transistor caused by improper selection or use.

(1) DC parameters.

1) Collector base reverse current I (CBO). When the emitter is open and a specified reverse voltage is applied between the collector and base, the leakage current in the collector junction is called I (CBO). The smaller the value, the better the thermal stability of the transistor. Generally, low-power transistors are around 10 μ A, while silicon transistors are smaller.

2) Collector emitter reverse current I (CBO), also known as penetration current. It refers to the leakage current of the collector when a specified reverse voltage is applied between the collector and emitter when the base is open circuited. The smaller the value, the better. Silicon tubes are generally small, around 1 μ A or less. If this value is found to be large during testing, the tube will not be easy to use.

(2) Extreme parameters.

1) When the β value of the transistor drops to half of its maximum value, the maximum allowable collector current I (CM) of the transistor is called the maximum allowable collector current. When the collector current Ic of the transistor exceeds a certain value, it will cause changes in certain parameters of the transistor, the most obvious of which is a decrease in β value. Therefore, in practical applications, Ic should be less than I (CM °)