Structure and use of pnp transistor, Electrical Engineering

Assignment Help:

Structure and use of PNP transistor:

The figure opposite is a schematic presentation of a PNP transistor related to two voltage sources. To construct the transistor conduct appreciable current (on the order of 1 mA) from E to C, VEB have to be above a minimum value occasionally considered to like the cut-in voltage. The cut-in voltage is generally about 600 mV for silicon BJTs at room temperature but can be different depending upon the type of transistor and its biasing. This applied voltage results the upper P-N junction to 'turn-on' permitting a flow of holes from the emitter into the base. In active mode, the electric field lay between the emitter and the collector (caused by VCE) causes the majority of these holes to cross the lower P-N junction into the collector to make the collector current IC. The remainder of the holes again combines with electrons, the majority carriers in the base, forming a current through the base connection to make the base current, IB. As displayed in the diagram, the emitter current, IE, is the total transistor current that is the sum of the other terminal currents (that is., IB=IB+IC).

In the figure, the arrows presenting current point in the direction of conventional current - the flow of holes is in similar direction of the arrows since holes carry positive electric charge. The ratio of the collector current to the base current is termed as the DC current gain, in active mode. This gain is generally 100 or more, but robust circuit designs do not depend upon the exact value. The value of this gain for DC signals is considered to as hFE, and the value of this gain for AC signals is considered to as hfe. Though, when there is no specific frequency range of interest, the symbol β is employed.

It should as well be noted that the emitter current is related to VEB exponentially. At room temperature, increment in VEB by approximately 60 mV increases the emitter current by a factor of 10. Since the base current is approximately proportional to the collector and emitter currents, they vary in similar way.


Related Discussions:- Structure and use of pnp transistor

Explain the methods of analysis for digital system, Q. Explain the Methods ...

Q. Explain the Methods of Analysis for digital system? Just as differential equations are used to represent systems with analog signals, difference equations are used for syste

Merits and demerits of stepper motor - stepper motor , Merits and Demerits ...

Merits and Demerits of Stepper Motor Followings  are the  merits and demerits  of stepper motors. Merits : a.They are compatible  with digital systems b.For the co

What do you mean by oscilloscope, Q. What do you mean by Oscilloscope? ...

Q. What do you mean by Oscilloscope? To measure time-varying signals (voltages and currents), an instrument known as an oscilloscope is employed. It can be used as a practical

Name the materials used in case of fuses, Name the materials used in case...

Name the materials used in case of Fuses . Also give reasons. Fuses : For rewirable fuses, copper-tin and lead-tin alloy is used. For HRC and cartridge fuses silve

Digital electronics, Design a logic circuit when to provide an output when ...

Design a logic circuit when to provide an output when any two or three of four switches are closed.

Conveyor, The FESTO conveyer consists of 600mm belt driven by a 24V d.c. mo...

The FESTO conveyer consists of 600mm belt driven by a 24V d.c. motor at a rate of 13 seconds per metre. A relay on the FESTO panel controls the motor operation and is wired for sou

Lime, what is the formula of lime water

what is the formula of lime water

Dc chopper - power supplies , DC chopper This is  one stage  conversio...

DC chopper This is  one stage  conversion  device  which is used for direct conversion of fixed  de voltage at a level to an adjustable dc voltage  at another  level.

Induction heating levitation, Using a levitation coil, you levitate a condu...

Using a levitation coil, you levitate a conductive object in the magnetic field and heat within that field. I have 2 sample report and I would like you to write some thing similar

Determine the mmf of the exciting coil, Q. For themagnetic circuit shown in...

Q. For themagnetic circuit shown in Figure, neglecting leakage and fringing, determine the mmf of the exciting coil required to produce a flux density of 1.6 T in the air gap. Them

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd