how a tarnsistor work ?

Answer 1

I assume you want to know how a TRANSISTOR works. I know that. Inside a transistor, there are two types of semiconductor: N-type, which had a substance is added, or was doped, to have more electrons; and P-type, which is doped to have places for electrons. When these two types are placed next to each other, electricity can flow from the N-type to the P-type. That is a diode. A transistor though, has one type in the middle with the other type on the other two sides (the order depends on the type of transistor: NPN or PNP). When the right charge is put in the middle one, the electricity can flow through the transistor.

So a transistor is just an electronic (as opposed to a manual) switch.

Answer 2

A transistor is an electronic component used as an amplifier within a circuit. There are two types of transistor NPN and PNP. When observed on a schematic "diagram", the symbol looks like a Y with a circle around it--there is a small arrowhead pointing outward indicating an NPN. A common circuit which uses a transistor is the power supply. This brings to mind a third transistor known as a field effect transistor. The FET is a solid state component which can be at the output stage of an ac/dc conversion power supply, the device would finally stabilize a dc supply. Another use for transistors is in the transistor radio. The circuit uses can vary, but the principal is amplification of a signal received by tarding current.

Answer 3

A transistor is made up of two types of semiconductor material divided into three sections. The most common type of transistor is the NPN type, where negetively charged material is divided by a positively charged material. The positively charged material is called the base and the two regions of negetively charged material are called the emitter and collector. When a negetive charge is placed on the base the positve region of the transistor becomes smaller and electrons from the emitter start to diffuse across the positively charged barrier. As the diffusion increases the current increases until the transistor reaches saturation which is where there is no longer any resistance to current flow. If the amount of voltage on the base is too small to allow diffusion or forward biasing no current will flow and the transistor will be in cut off. Transistors are used in amplifier circuits to provide an increase from stage to stage. But how much the increase is and wether it is a voltage, current, or power increase is determined by the configuration of the entire transistor circuit.

Answer 4

Two comments on the answers above, which are generally on the right track

First, n-type and p-type semiconductors are not charged, they are neutral. The n-type has more electrons free to move under the influence of an electric field, while the p-type has electon vacancies (holes) that move like positive charges.

Second, how a transistor works (briefly and simplified):

When n and p materials are joined, they exhibit diode behaviour: the resistance to current is much higher in one direction than the other (orders of magnitude different). In a transistor two n-layers are separated by a thin p layer (or vice versa). This is like two diodes back to back. If we send current in the low resistance direction from the n-layer to the p-layer, most of the current will flow right through the thin p-layer into the n-layer on the other side. It will appear that current is coming out the wrong way from a diode (out the high impedance direction). Thus what went in at low resistance comes out of a high resistance. The device has "tranferred" or "transformed" the resistance of the input current from low to high, therefore it is called a transistor.

The device can amplify since only a small voltage is needed to generate the input current, yet the output can drive a resistor to much higher voltages. The output voltage is isolated from the input by the high resistance of the output diode.