product description 

Product details

The working principle of the transistors on the circuit board is mainly based on the characteristics of the semiconductor material. A transistor usually consists of three regions: an emission region, a base region, and a collector region. These regions are connected to each other through PN junctions (interfaces formed by P-type semiconductors and N-type semiconductors).

The working principle of a transistor can be simply described as:

Cut-off state: When the base voltage of the transistor is below a certain threshold (called the on voltage), electrons in the emitter region cannot efficiently travel through the base region to the collector region, so almost no current flows from the collector to the emitter. At this point, the transistor is in the off state and can be thought of as an off switch.

Amplification state: When the base voltage is increased above the on voltage, electrons in the emission region begin to be attracted by the base voltage and pass through the base region to the collector region. Because the base region is thin and the doping degree is low, it has a weak control effect on the current, so a small change in the base current can cause a relatively large change in the collector current. This is the amplification of transistors. In this state, the transistor can be viewed as a controlled source of current.

Saturated state: When the base voltage continues to increase, the electrons in the emission region will flood into the base region, resulting in an increase in the charge concentration in the base region, which weakens the control effect of the base voltage on the collector current. When the collector current reaches its maximum value, the transistor enters a saturated state. At this point, no matter how the base voltage changes, the collector current will remain the same.

In circuit boards, transistors are often used to achieve various functions, such as amplification, switching, voltage regulation, and so on. By controlling the base voltage of the transistor, the size and direction of the collector current can be precisely controlled, so as to achieve various functional requirements of the circuit.

Product Parameter

Model Number: 0-49017-65

Origin:IN

India series of products