See for example http://www.datasheets360.com/pdf/7308997814572458562
In general, terminals are identified by number and name, with reference to the physical appearance of the transistor package.
Three.
The terminals of a BJT (bipolar junction transistor) are the emitter, base, and collector. One common method to identify these terminals is to look at the physical package of the transistor. The emitter is usually connected to the most heavily doped region and is often indicated on the package. The base is usually the middle terminal, and the collector is often connected to the remaining terminal.
UJT (UniJunction Transistor): It is a transistor with only one junction and three terminals: an emitter (E) and two bases (B1 and B2). BJT (Bipolar Junction Transistor): This type of transistor consists of two junctions and three terminals, namely Emitter "E", Base "B" and Collector"C". There are two types of BJT, i) PNP and ii) NPN.
Identifying BJTs and FETs on the circuitIt is in fact possible to identify transistors in circuits. However, this depends on one's familiarity with the different types of BJT and FET constructions. Since the transistor is a three-terminal device, it is easy to differentiate it from other circuit elements such as resistors, capacitors and inductorswhich are all two-terminal devices. The only exceptions to this may include regulators; which though are not transistors are provided with three terminals.
mosfets come in 2 shape 1.round shaped(like bjt):hold it such that the pins face upwards and the knoch perpendicular to your eyes,then name pins as G,D,S in anticlock wise direction. 2.almost squre shaped.hold it perpendicular to your face ,then name them G,D,S from left to right
Disadvantage:Easy to damage when compared to BJT
Bipolar junction transistor(BJT)
If you want to find DC gain (Hfe) of a BJT transistor like BC547, then you need to look in its datasheet. You can easily find a datasheet for BC547 just by googling it. Once you found it, then you will find a graph for DC current gain in the datasheet. The x-axis of the graph will be the collector current (Ic) and the y-axis will be the gain (Hfe). As you will see from the graph the gain is dependent on the collector current Ic. Therefore first determine what collector current you want to be flowing, then use the graph to find what the DC gain will be. Then you can find what base current Ib you need to inject in order to establish the necessary collector current Ic. The relationship is Ic = Hfe*Ib.
They are NPN and PNP. BJT mean bipolar junction transistors. there are two P-N junctions in BJT transisters.
FET's (field effect transistors) are unipolar devices because unlike BJT's that use both electron and hole current, they operate only with one type of charge carrier. BJT is a current-controlled device; that is the base current controls the amount of collector current. FET is a voltage-controlled device, where voltave between two of the terminals (gate and source) controls the current through the device. BJT's have a low input impedance ( ~1k -3k ohms), while FET's have a very high input impedance (~10^11 ohms). Consequently FET's have a lower power consumption. BJT's produce more noise than FET's . FET's have a slower switching speed . BJT's are subject to thermal runway while FET's are immune to this problem. BJT's have a higher cutoff frequencey and a higher maximum current then FET's. FET's are easy to fabricate in large scale and have higher element density the BJT's.
because the fet is made out of carbon metal oxide and the bjt is made out of silicon or germanium
BJT is Bipolar junction transistor FET is Field effect Transistor It is a current controlled device It is voltage controlled device