Transistors Overview

Transistors
NPN and PNP Transistors

We looked at the construction and operation of NPN and PNP bipolar junction transistors (BJTs), as well as field-effect transistors (FETs), both intersections and insulated doors. Then let's make a general summary of transistors in this article.

  • The bipolar junction transistor (Bjt) is a three-layer device consisting of two semiconductor diode junctions connected to each other, one forward biased and one reverse biased.
  • There are two main types of bipolar connection transistors. (BJT) NPN and PNP transistor. it is "current-powered devices" where a much smaller base current causes a larger emitter to the collector current, which themselves are almost equal.
  • The arrow in a transistor symbol represents the traditional current flow.
  • The most common transistor connection is the common emitter (CE) configuration. However, a common base (CB) and a common collector (CC) are also available.
  • A bias voltage is required for the AC amplifier to work.
  • While the base-emitter junction is always forward biased, the collector-base junction is always reverse biased.
  • The standard equation for currents flowing in a transistor is given as follows: IE = IB + IC
  • Collector or output characteristics curves can be used to find Q with variations in the base current that determine the working range of Ib, Ic, or β, where a load line can be created to determine an appropriate working point.
  • A transistor can also be used as an electronic switch between saturation and cutting zones to control devices such as lamps, motors and solenoids.
  • Inductive loads, such as DC motors, relays and solenoids, require an inverted biased "flywheel" diode placed along the load. This helps prevent any induced re-emf produced when the load is "off" from damaging the transistor.

Field Effective Transistor Features

  • Field-effective Transistors or FET's are "Voltage-powered devices" and can be divided into two main types: connection door devices called Jfets and insulated door devices called Igfets, or more commonly known as Mosfets.
  • Iso-gate devices can also be defeated divided into types and types of development exhaustion. All forms are available in both N-channel and P-channel versions.
  • FET's have very high input resistance. Therefore, little or no current (MOSFET types) flow into the input terminal, making them ideal for use as electronic switches.
  • Mosfet's inlet impedance is even higher than JFET's due to its insulating oxide layer. Therefore, static electricity can easily damage MOSFET devices.
  • When voltage is not applied to an improvement FET door, the transistor is in a "closed" state, similar to an "open switch".
  • FETO has much higher current gains compared to bipolar connection transistors.
  • The most common FET connection is the common source (CS) configuration, but common gate (CG) and common drain (CD) configurations are also available.
  • MOSFETs can be used as ideal switches due to very high channel "off" resistance, low "on" resistance.
  • A negative voltage must be applied to the door to "turn off" the N-channel JFET transistor.
  • A positive voltage must be applied to the door to "turn off" the P-channel JFET transistor.
  • N-channel depletion mosfets are "closed" when a negative voltage is applied to the door to form the depletion zone.
  • P-channel depletion mosfets are "closed" when a positive voltage is applied to the door to form the depletion zone.
  • N-channel development mosfets are "on" when a "+and" (positive) voltage is applied to the door.
  • P-channel development Mosfets are in an "on" state when the " – and" (negative) voltage is applied to the door.

Important Differences Between FET and Bipolar Transistor

Transistors
Important Differences Between FET and Bipolar Transistor

Field Effective Transistor Scheme

Transistors
Field Effective Transistor Scheme