IC's function on PCB assembly

What is the function of IC on PCB assemly products？

Integrated circuit English: integrated circuit, abbreviated as IC; or microcircuit (microcircuit), microchip (microchip), wafer/chip (chip) in electronics is a kind of circuit (mainly including semiconductor equipment, but also passive components Etc.) It is miniaturized and is often manufactured on the surface of a semiconductor wafer.

(1) The function of IC on PCBA products is current amplification. Under the action of a certain bias voltage, the triode makes it work in the amplifying region. At this time, when the base current Ib increases, the collector current Ic. It also increases, and the increase in Ic is β times Ib, that is, a small change in Ib can cause a large change in Ic.
 (2) It has the equivalent function of a variable resistor on PCBA. If the size of the base current of the triode is controlled, the collector current Ic can be changed. With this feature, the triode can act as a variable resistance for current regulation.
 (3) Can be used as a non-contact switch when Wave Solder for PCBA. If the characteristics of the saturation state and the cut-off state of the blue transistor are used to control the base current, the transistor is saturated when Ib≥Ics/β. At this time, the resistance between the emitter and the collector is very small, which is equivalent to the switch on: when When the base current Ib is less than or equal to 0, the triode is off. At this time, the resistance between the emitter and the collector is very large, which is equivalent to the switch off. Therefore, to control the on and off of the switch, you only need to control the size of the base current.