Transistors are semiconductor devices with no less than three outputs. In certain situations, they are able to amplify power, generate oscillations, or transform a signal. There are a lot of different designs of these devices, and among them is a pnp transistor.
Transistors are classified by semiconductor material. They come from silicon, germanium, etc.
If a two-region transistor has two hole conductivity, it is called a “direct conductivity transistor,” or “a pnp junction transistor." A device in which two regions have electronic conductivity is called a reverse conductivity transistor, or with an npn junction. Both transistors work the same way, and the difference lies solely in polarity.
Where is the pnp transistor used?
Depending on what characteristics the transformer has, it 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, the current of the input circuit is controlled. Small changes in the input parameters lead to an even larger change in the output current and voltage. This gain property is used in analog technology (radio, analog TV, communications, etc.).
Nowadays, a bipolar pnp transistor is used for analog technology . But another, very important industry - digital technology - almost abandoned it and uses only the field. A bipolar pnp transistor appeared much earlier than a field -effect one , because in everyday life it is simply called a transistor.
Execution and parameters of transistors
Transistors are structurally manufactured in plastic and metal cases. Given the different purpose of the transistors, these devices are selected according to certain parameters. For example, if you need a transistor to amplify high frequencies, it must have a high signal amplification frequency. But if the pnp transistor is used in a current stabilizer, it must have a high collector operating current.
Reference literature contains the main characteristics of transistors:
- Ik - working (maximum allowable) collector current;
- h21e is the gain;
- Fgr - maximum gain frequency;
- Pk is the collector power dissipation.
Phototransistors
A phototransistor is a device that is sensitive to the light flux that irradiates it. In the sealed case of such a transistor, a window is made, for example, of transparent plastic or glass. Radiation through it falls into the base zone of the phototransistor. If the base is irradiated, then charge carriers are generated. The phototransistor will open when the charge carriers go into the collector junction, and the more the base is illuminated, the collector current will become more significant.
Without transistors, modern electronics cannot be imagined. Almost 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.