Understand Transistor--electronic Circuit Device

Semiconductor Transistor, also known as transistor, you can say that it is the most important electronic circuit device.
By: jojoly
 
March 3, 2010 - PRLog -- Semiconductor Transistor, also known as transistor, you can say that it is the most important electronic circuit device. Its primary function is the role of current amplification and switching. As the name suggests transistor has three electrodes. Diode is a PN structure into, while the transistor into by the two PN structure, shared an electrode into the base transistor (indicated with the letter b). The other two electrodes as the collector (with the letter c indicated) and emitter (with the letter e indicated). Because different combinations, forming a kind of a NPN type transistor, the other is a PNP-type transistor.
1. Concept:
  Semiconductor Transistor, also known as bipolar transistors, transistor, known transistor is a current controlled semiconductor devices.
  Role: the weak signal amplification into a convergent value of the larger signal, but also for non-contact switch.

2. Triode classification:
a. according to material points: silicone tube, germanium tube
b. according to the structure points: NPN, PNP
c. by function: switch, power tube, Darlington, photosensitive tubes.

3. Triode main parameters:
a. characteristic frequency fT: When f = fT, the transistor current amplification function completely lost. If the operating frequency is greater than fT, the circuit will not work properly.
b. Operating voltage / current: Using this parameter you can specify the use of tube voltage and current.
c. hFE: current magnification.
d. VCEO: collector-emitter reverse breakdown voltage, said that when the critical saturation of the saturation voltage.
e. PCM: the maximum allowable power dissipation.
f. Package Type: Specify the appearance of the tube shape, if other parameters are correct and will result in a different package components can not be.

4. To determine base and transistor type:
    Assume that a transistor has "base" will pen the black table base, on the assumption that access, and then in turn received a red table pen on the other two electrodes, if the resistance were measured twice a large (about several tens of K to K), or are small (several hundred to a few K), right pen for the table repeat the above measurements, if the resistance measured at two opposite (very small or have a very heavy), you can determine the base assumption is correct, Otherwise, the other assuming a very "base", repeat the test to determine the base.
    When the base is confirmed, then the black table base pen, red pen table pen base it is then, if the measured polarization resistance values are very small, then the transistor is NPN, contrary to PNP.
To determine the collector C and emitter E, in order to NPN as an example:
    The black table pen posed as a collector connected to C, red table pen received a hypothetical emitter E, and B, and C by hand pinch the most, read out the header as shown in C, E resistance value, and then red, black table pen reverse re-test. when the first resistance smaller than the second meeting shows that the original assumption.

Body structure and type of transistor

    Transistor is a semiconductor, one of the basic components, with current amplification is the core component of electronic circuits. Transistor is a semiconductor substrate produced two in close proximity of the PN junction, the two PN junction to the semiconductor block is divided into three parts, the middle part is the base area, both sides of the part of the emitter and collector areas, arrangement of a PNP and NPN two,
From the corresponding electrode leads the three districts, namely, e base b emitter and collector c.
    Between the emitter and base area of the PN junction is called emission knots, collector area and the PN junction between base region is called the collector. Very thin base region, while the emitter thick, impurity concentration of large, PNP-type transistor emitter "launching" the hole, its direction of movement and current in the same direction, so the arrow to where the emitter; NPN-type transistor emitter "launching "is that free electrons, its direction of movement and current in the opposite direction, so the emitter arrow out. Emitter arrow out. Emitter arrow is pointing in the forward voltage of PN junction under the direction of the turn-on. Silicon and germanium Transistor Transistor PNP type and NPN type has two types.

Transistor package form and pin identification
  Transistor package commonly used form of metal packaging and plastic packaging two categories, the arrangement of the pins have certain laws,
  Bottom View location to place, so that three pins constitutes the apex of the isosceles triangle, from left to right followed by ebc; for small and medium-power transistor according to plan so that plastic plane towards themselves, three pins down place, then the left -to-right order of ebc.

At present, the country there are many types of transistor types, different arrangements of pins in the use of pins arranged in uncertain transistor, each pin must be measured to determine the correct location, or find transistor manuals, clearly transistor characteristics and the corresponding technical parameters and information.
click http://www.super-e-world.com to know more
End
Source:jojoly
Email:***@gmail.com Email Verified
Tags:Electronic, Circuit, Device
Industry:Electronics



Like PRLog?
9K2K1K
Click to Share