Transistor Drive Load Tips and Choices Considerations

In electronic production, it often involves the need to control buzzers, relays, motors and other components. It is found that different connections of transistor loads have different effects. Some connections may even lead to unreliable circuit operation. The selection and use of load drive circuits, drive circuits, and components are discussed.

Transistors (also known as triodes) can be divided into NPN type and PNP type. Currently, commonly used NPN type transistors have 8050, 9013, 2N5551, etc. PNP type transistors have 8550, 9012, 2N5401 and so on.

1, the common load of the drive circuit

Figure 1 shows a typical circuit for driving various loads of NPN-type and PNP-type transistors. It is required to get the maximum power on the load, and the minimum power is consumed on the transistor.

Figure 1 Typical circuit for driving various loads of NPN type and PNP type transistors

2, drive circuit and component selection

Using a transistor to drive a load primarily utilizes the switching characteristics of the transistor, that is, controlling the turn-on and turn-off of the load by controlling the switching of the transistor between the saturation region and the cut-off region. Then some electronic enthusiasts will ask: When do you choose the NPN transistor drive circuit? When do you choose a PNP transistor to drive the load? For the same type of transistor, how do you choose the specific model of the transistor? How should the base resistance be selected? Here is a brief description of these issues.