How does NPN and PNP transistor work?

How does NPN and PNP transistor work?

In an NPN transistor, a positive voltage is given to the collector terminal to produce a current flow from the collector to the emitter. In a PNP transistor, a positive voltage is given to the emitter terminal to produce current flow from the emitter to collector.

What is transistor how it works?

A transistor works when the electrons and the holes start moving across the two junctions between the n-type and p-type silicon. By turning a small input current into a large output current, the transistor acts like an amplifier. But it also acts like a switch at the same time.

What is an NPN transistor used for?

NPN transistors are primarily used in switching applications. NPN transistors are used in amplifying circuit applications. NPN transistors are used in the Darlington pair circuits for amplifying weak signals. NPN transistors are used in applications we need sinking current.

Is PNP normally open?

PNP – (PNP transistor) NO – normally opened, that means there is no voltage on the output while the sensor is not actuated (see picture, PNP sensor output connector is no. 4).

What is NPN and PNP transistor?

NPN and PNP refer to the arrangement of the pieces that make up the transister. An NPN transistor has a piece of P-type silicon (the base) sandwiched between two pieces of N-type (the collector and emitter). In a PNP transistor, the type of the layers are reversed. Below is a typical cross section of a transistor.

What is PNP transistor with diagram?

The structure of a PNP transistor is depicted in the diagram below. The emitter and base junctions are forward biased, while the collector and base junctions are reverse biased. The forward biased emitter attracts electrons to the battery, causing current to flow from the emitter to the collector.

Where are PNP transistors used?

Application of PNP Transistor

  1. They are used as switches.
  2. They are used for conducting current in heavy motors.
  3. Amplifying circuits also have PNP transistors in them.
  4. The use of these transistors is also made in robotic applications.

Is NPN better than PNP?

As the electrons have higher or faster mobility than holes, the conductivity also more. For this reason, NPN transistors are more preferable than PNP transistors because the NPN transistor provides more conductivity. We know that in electronic circuits all the negative(-ve) or common terminals are grounded.

What is the purpose of a NPN transistor?

Another common application for NPN transistors is to use them as an amplifier, in which a small increase in the input voltage induces a large change in the output voltage. NPN transistors are used for this purpose in almost all phones electronic devices in which sound amplification or reproduction is required.

Why do we use NPN transistor?

NPN transistors are used when you want to sink a current; i.e. current flows into the collector. PNP transistors are used when you want to source a current; i.e current flows out of the collector. As a result of this, NPN transistors usually have their emitter connected to the low side of the supply.

How do NPN and PNP transistors operate?

The operation of the PNP and NPN transistors mainly utilizes holes and electrons. These transistors can be used as amplifiers, switches and oscillators. In PNP transistor, the majority charge carriers are holes, where in NPN the majority charge carriers are electrons.

What are the working principles of transistor?

Working Principle of Transistors. When no voltage is applied across the transistor, diffusion of free electrons across the junctions produces two depletion layers . For each depletion layer, the barrier potential is about 0.7 V at 25°C for a silicon transistor and 0.3 V for a germanium transistor.