Transistors are semiconductor devices,which have at least three conclusions. In certain situations, they are capable of amplifying power, generating oscillations or converting a signal. There are a lot of very different designs of these devices, and among them is a PNP transistor.
Classify transistors for semiconductor material. They come from silicon, germanium, etc.
If a transistor of three regions has twohole conductivity, it is called a "direct-transistor", or "transistor with a pnp transition". A device in which two regions have electronic conductivity is called a transistor with a reverse conductivity, or with an npn transition. Both transistors work identically, and the difference is exclusively in polarity.
Where is the PNP transistor used?
Depending on what characteristics of theit can be used for a variety of purposes. As already mentioned, a transistor is used to generate, convert and amplify electrical signals. Due to the fact that the input voltage or current changes, current input current control is controlled. Small changes in the parameters at the input lead to an even greater change in the current and voltage at the output. This gain feature is used in analog technology (radio, analog TV, communication, etc.).
Nowadays, analogue technology is usedbipolar pnp-transistor. But another, very important industry - digital technology - almost abandoned it and uses only the field one. The bipolar pnp-transistor appeared much earlier than the field one, because it is simply called a transistor.
Execution and parameters of transistors
Transistors are structurally manufactured inplastic and metal housings. Given the different purpose of the transistors, these devices are selected according to certain parameters. For example, if a transistor is needed to amplify high frequencies, it must have a high frequency of signal amplification. And if the pnp transistor is used in a current stabilizer, it must have a high operating collector current.
Reference literature contains the main characteristics of transistors:
- Ik - working (maximum permissible) collector current;
- h21e is the gain;
- Fgr - the maximum frequency of amplification;
- Pk is the power dissipated by the collector.
Phototransistors
A phototransistor is a device sensitive tolight flux, which irradiates it. In the hermetic case of such a transistor, a window is made, for example, of transparent plastic or glass. Radiation through it enters the base of the phototransistor. If the base is irradiated, then charge carriers are generated. The phototransistor opens when the charge carriers pass into the collector junction, and the more the base is illuminated, the collector current becomes more significant.
Without transistors, one can not imagine a modernelectronics. Virtually no serious device can do without them. Over the years of application and improvement, transistors have changed significantly, but the principle of their operation remains the same.
