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In order to bias a bipolar junction transistor on, you need to forward bias the base-emitter junction at the same time you forward bias the collector-emitter junction, and the ratio of collector current over base current must be somewhat less than hFe, the transistor's gain. This is known as saturated, or non-linear mode, operation. In practice, we drive the base much harder than the calculated required current, so as to minimize dependency on varying hFe's for various transistors.
Turning the transistor off is a simple matter of eliminating the base current.
In the case of the NPN transistor, the base and collector would need to be more positive than the emitter. In the case of the PNP, they would need to be more negative.
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What does the arrow in bipolar junction transistor symbol represent?
There a two types of bipolar transistors PNP and NPN . This refers to the doping elements used in the silicon components of this 3 layer device with base always in the middle. The arrow is the emitter wire and shows direction of conventional current flow(positive to negative) NPN transistors (generally used in negative earth circuits) have the arrow pointing away from the base connection PNP transistors ( generally used in circuits with positive earth) have the arrow pointing towards the base connection.
What is the voltage required to turn on a silicon transistor?
basically a .6v to .7v is required to saturate the transistor The collector to emitter region will begin to become conductive once the base emitter junction is forward biased enough. Depending on the current through the base-emitter junction, the forward voltage drop could be anywhere from around .55 to .8 volts. .6 to .7 volts minimum is a good approximation not taking into account the device characteristics. Bipolar transistors (npn pnp) are current to current devices not voltage to current. This is for silicon transistors, germanium devices are lower forward voltage devices. Around .3 volts.
How do you know if a transistor is a PNP or an NPN?
To know if a transistor is PNP or an NPN,the following should be verified:For a PNP transistor, the base-collector junction is forward biased while the base-emitter junction is reversed biased.For an NPN transistor, the base-emitter junction is forward biased while the base -collector junction is reversed biased.
How many diodes in a transistor?
There are two semiconductor junctions. Transistors are designated as NPN or PNP and a diode is an NP or PN junction depending on direction of current flow. However, the function of a transistor is different than two back to back diodes.
What is the difference between the UJT and BJT transistors?
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.
What is btj transistors?
They are NPN and PNP. BJT mean bipolar junction transistors. there are two P-N junctions in BJT transisters.
What are PNP and NPN?
In most discrete bipolar junction transistors the substrate is the collector. In monolithic integrated circuits the bipolar junction transistors are electrically isolated from the substrate, either by reversed biased junctions or insulator (e.g. sapphire). Some older bipolar junction transistor types (usually made with germanium) the substrate is the base. In bipolar point contact transistors the substrate was the base.
What is the difference between BJT and NPN transister?
Mainly there are two types of transistors. They are BJT (Bipolar Junction Transistors) and FET(Field Effect Transisters). In BJT, there are two types called PNP and NPN. Actually NPN means a BJT transister.
How many pn junction does transistor contain?
Two, either in NPN or PNP transistors
Is it emitter-base junction should be reversed for both npn and pnp transistors acts as a amplifiers?
no, the emitter base junction should be foward for both npn and pnp to act as amplifiers.
Is bipolar transistor is made up of one NP junction?
no, 2 junctions. NPN or PNP
What does the arrow in bipolar junction transistor symbol represent?
There a two types of bipolar transistors PNP and NPN . This refers to the doping elements used in the silicon components of this 3 layer device with base always in the middle. The arrow is the emitter wire and shows direction of conventional current flow(positive to negative) NPN transistors (generally used in negative earth circuits) have the arrow pointing away from the base connection PNP transistors ( generally used in circuits with positive earth) have the arrow pointing towards the base connection.
Why are npn transistors used more often than pnp transistors?
The primary reason that NPN transistors are used more often than PNP transistors is that they usually operate faster (at higher frequencies) because the mobility of the current carriers in NPN transistors (electrons) is much higher than that of the current carriers in PNP transistors (holes).
What are characteristics of transistors?
These are the Key characteristic specification of a Bipolar Junction transistor Vceb Breakdown voltage Vcesat Saturation voltage Vbe Sat Maxximum Forward current Leakage Current Power dissipation Thermal resistance theta-JC and theta-JA Hfe Polarity NPN or PNP Frequency
Which transistoris widely used?
Npn transistors are widely used
How do you know if a transistor is a PNP or an NPN?
To know if a transistor is PNP or an NPN,the following should be verified:For a PNP transistor, the base-collector junction is forward biased while the base-emitter junction is reversed biased.For an NPN transistor, the base-emitter junction is forward biased while the base -collector junction is reversed biased.
What is the voltage required to turn on a silicon transistor?
basically a .6v to .7v is required to saturate the transistor The collector to emitter region will begin to become conductive once the base emitter junction is forward biased enough. Depending on the current through the base-emitter junction, the forward voltage drop could be anywhere from around .55 to .8 volts. .6 to .7 volts minimum is a good approximation not taking into account the device characteristics. Bipolar transistors (npn pnp) are current to current devices not voltage to current. This is for silicon transistors, germanium devices are lower forward voltage devices. Around .3 volts.
