{"id":2092,"date":"2024-07-19T17:15:03","date_gmt":"2024-07-19T11:45:03","guid":{"rendered":"https:\/\/study.madeeasy.in\/?p=2092"},"modified":"2025-07-16T15:16:23","modified_gmt":"2025-07-16T09:46:23","slug":"what-is-the-function-of-a-transistor-in-an-electronic-device","status":"publish","type":"post","link":"https:\/\/www.madeeasy.in\/study\/ec\/electronic-devices-circuits\/what-is-the-function-of-a-transistor-in-an-electronic-device","title":{"rendered":"What is the function of a transistor in an electronic device?"},"content":{"rendered":"

The transistor was invented by Dr. William Shockley and Dr. John Barden at Bell Laboratory in America in 1951. The transistor is a basic building block of all modern electronic systems. It is a three terminal device.<\/p>\n

The output voltage, current or power are controlled by the input current in transistor therefore it is called a current controlled device.<\/p>\n

BJT stands for Bipolar junction transistor because the transistor operation is carried out by two types of charge carriers majority carriers and minority carriers.<\/p>\n

Device Structure<\/h2>\n

A transistor is a single crystal of Silicon (Si) or Germanium (Ge). A transistor can be of two types: NPN or PNP. It has three separately doped regions and two pn junctions. The junctions are formed by sandwiching either P<\/em>-type or N<\/em>-type semiconductor <\/a>layers between a pair of opposite types as shown in figure below.<\/p>\n

The three terminal connections are called emitters, base and collector. The width of the base region is small compared to the minority carrier diffusion length. Generally the sequence of length of the three regions are W<\/em>B<\/sub> <\/em>< W<\/em> E<\/sub> <\/em>< W<\/em> C<\/sub> <\/em>.<\/p>\n

\"NPN-Transistor\"<\/p>\n

Note:<\/h5>\n

The term transistor was derived from the words TRANSFER and RESISTOR. The term was adopted because it best describes, the operation of a transistor, which is the transfer of an input signal current from a low resistance circuit to a high resistance circuit.<\/p>\n

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