Transistors and types of transistors

Study what you need to know about transistors and types of transistors in this post. furthermore, to better understand transistors and their types, read all the articles in this page.

WHAT ARE TRANSISTORS

 

Images of transistors

Transistors are three (3) terminals semiconductor devices that are use as either electronic switches or electrical signal amplifiers. In transistors; if a current or voltage is applied that is to say “input” to a pairs of terminals of the transistor, will control the flow of current in the other pair of terminals. The controlled current or voltage is the output voltage or current and this can be greater than the input voltage or current. Transistors are used widely in most electronic devices these days and are embedded also in Integrated Circuits (ICs) because of their unique functions to either switch or amplify electronic signals. See transistor acting as switch here and transistor acting as amplifier here.

TYPES OF TRANSISTORS

Transistors are classified into two (2) types;

  1. Bipolar Junction Transistor (BJT)
  2. Field Effect Transistor (FET)
BIPOLAR JUNCTION TRANSISTOR (BJT) AND TYPES

Bipolar Junction Transistor BJT is the types of transistors that have two charges carriers. That is electron and hole.

TYPES OF BIPOLAR JUNCTION TRANSISTOR

Bipolar Junction Transistors come in two (2) different types. These are:

  1. NPN Bipolar Junction Transistor (NPN BJT)
  2. PNP Bipolar Junction Transistor (PNP BJT)

 

NPN BIPOLAR JUNCTION TRANSISTOR

NPN Bipolar Junction Transistor (BJT) which is one of the two types of Bipolar Junction Transistors (BJTs) is a type that has three regions layers semiconductors where P-type being the Base (B) layer is doped between the two other N-types. That is; Emitter (E) and Collector (C) layers forming the NPN layers. By applying positive potential difference (Pd) across the base (B) of the transistor to its emitter (E) (making the base higher than the emitter) and also across the collector to the emitter at the same time, the transistor becomes active.  When a current enters the base of the transistor, is then amplified thereby causing a larger collector and emitter current to……….READ THIS IN DETAIL

Bipolar Junction Transistor (BJT) Operation Regions

Bipolar Junction Transistors (BJT) has basically three regions of operations these are;

  1. Cut off region (FULLY OFF)
  2. Saturation region (FULLY ON)
  3. Active region.
CUT OFF REGION (FULLY OFF)

In cut off or fully off region, the transistor is bias in such a way that both junctions are reverse so that no current will pass from the emitter (E) to the collector (C). In this mode, the transistor is in OFF mode.

When we study the below circuits, two PN-junction diodes are configure to form two types of layers. These are NPN layers and PNP layers. In NPN layers; P-dope is the common junction while in PNP layers; N-dope is the common junction.…….READ THIS

SATURATION REGION (FULLY ON)

A transistor is said to be saturated (Fully ON) when it is biased in such a way that current passes from the Emitter (E)  to the Collector (C). In NPN and PNP bipolar junction transistors (BJTs), connecting the base (B) to the collector (C) makes the PN-junction from the base (B) to the emitter (E) to be forward bias. As a result of this, the base (B) to the collector (C) of the transistor shorts thereby causing high current to flow from the emitter (E) to the collector (C).………READ THIS

ACTIVE REGION

In active region the transistor is bias so that the base (B) measures a higher potential difference (Pd) to the emitter (E) but lower than the collector (C) to the emitter (E). In this region the transistor is always active. This is the biasing mode or region which transistor amplifiers use for their operations…………READ THIS

FIELD EFFECT TRANSISTOR (FET) AND TYPES OF FIELD EFFECT TRANSISTOR

Field Effect Transistors (FETs) also called unipolar transistors are three (3) terminals type of transistors that utilizes only single charge carrier type which could be electrons for P-Channel and holes for N-Channel. This type of transistors have high input impedance at low frequencies compared to the other type i.e. Bipolar Junction Transistor (BJT) which have low input impedance. The three terminals are name; Source (S), Gate (G), and Drain (D). The resistance of the conduction between the source (S) and the………………READ THIS

READ ALSO THESE

Transistor acting as an amplifier or Transistor acting as a switch

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