Because a transistor's collector current is proportionally limited by its base current, it can be used as a sort of current-controlled switch. A relatively small flow of electrons sent through the base of the transistor has the ability to exert control over a much larger flow of electrons through the collector.
Since the base in an n-p-n transistor is kept very thin, very few electrons get to recombine with holes and escape out of base, most of the electrons are injected from emitter into the collector. As a result, Base-current is very small. Whereas the Collector-current is almost equal to the Emitter-current.
The base is excited by a very low current. That turns the transistor on so that a higher amount of current flow comes out.
A Darlington amplifier consists of two bipolar junction transistors (BJTs) connected in a configuration that allows the current amplified by the first transistor to drive the second transistor. This arrangement results in a very high current gain, as the output current of the first transistor becomes the input current for the second. The input signal is applied to the base of the first transistor, which greatly amplifies it before passing it to the base of the second transistor for further amplification. The overall effect is a significant increase in both current and voltage gain, making it useful in various applications where high gain is required.
A transistor has three leads, called the base, the collector, and the emitter. The voltage of the base (in relation to the ground) determines whether and how much current flows from the collector to the emitter. An NPN transistor can be off, meaning that there is no (or very little) voltage from the base; partly on, meaning that there is some voltage from the base; or saturated, meaning that it is receiving full voltage from the base. A saturated transistor allows the current to flow from the collector to the emitter unopposed; a partly on transistor provides some resistance; and a transistor that is off provides full resistance. A PNP transistor is similar to an NPN transistor except it performs the opposite function: when it is saturated, the current is fully resisted; when there is no voltage from the base, the current is not at all resisted; and when it is partly on there is some resistance. In sum, a transistor controls the flow between the collector and the emitter based upon the voltage of the base. this is carbage. a transistor is basicaly two diodes back to back base being common TO BOTH DIODES because of inpurity doping on purpose at the depletion region the transistor will control the current flow on the other diode. Once it reaches saturation both diodes conduct therefore current can flow in BOTH DIRECTIONS ACROSS IT.
on or off
base current is very small and we should apply ainput on base current
as the base current is very small compared to the emitter current,the collector current is nearly equal to the emitter current..
as the base current is very small compared to the emitter current,the collector current is nearly equal to the emitter current..
Base of transistor is made thin just to get Collector current equal to Emitter current.
Small is relative term, current gain of the transistor decides how small base current would be than collector current. Most of the emitter current of electrons diffuses through the thin base into the collector. Moreover, modulating the small base current produces a larger change in collector current.Small is relative term, current gain of the transistor decides how small base current would be than collector current. Most of the emitter current of electrons diffuses through the thin base into the collector. Moreover, modulating the small base current produces a larger change in collector current.Small is relative term, current gain of the transistor decides how small base current would be than collector current. Most of the emitter current of electrons diffuses through the thin base into the collector. Moreover, modulating the small base current produces a larger change in collector current.
Since the base in an n-p-n transistor is kept very thin, very few electrons get to recombine with holes and escape out of base, most of the electrons are injected from emitter into the collector. As a result, Base-current is very small. Whereas the Collector-current is almost equal to the Emitter-current.
The base is excited by a very low current. That turns the transistor on so that a higher amount of current flow comes out.
The input current of transistor is approximately equal to output current .Suppose in common base configuration the emmiter current is approximately equal to collector current if neglect the very small value of bae current.Even though the input resistance is not equal to output resistance,the currents are same ,so we can reliase that the transistor transfers resistance to get same currents at both ends.
A Darlington pair uses two transistors connected to behave as a single transistor with a very high current gain (beta). Transistor-1 has its collector connected to the collector of transistor-2. Transistor-1 has its emitter connected to the base of transistor-2. The base of transistor-1 with the emitter and collector of transistor-2 is used as a single transistor.
small, fast and use very little current (high-efficiency).
A transistor has three leads, called the base, the collector, and the emitter. The voltage of the base (in relation to the ground) determines whether and how much current flows from the collector to the emitter. An NPN transistor can be off, meaning that there is no (or very little) voltage from the base; partly on, meaning that there is some voltage from the base; or saturated, meaning that it is receiving full voltage from the base. A saturated transistor allows the current to flow from the collector to the emitter unopposed; a partly on transistor provides some resistance; and a transistor that is off provides full resistance. A PNP transistor is similar to an NPN transistor except it performs the opposite function: when it is saturated, the current is fully resisted; when there is no voltage from the base, the current is not at all resisted; and when it is partly on there is some resistance. In sum, a transistor controls the flow between the collector and the emitter based upon the voltage of the base. this is carbage. a transistor is basicaly two diodes back to back base being common TO BOTH DIODES because of inpurity doping on purpose at the depletion region the transistor will control the current flow on the other diode. Once it reaches saturation both diodes conduct therefore current can flow in BOTH DIRECTIONS ACROSS IT.
A Darlington amplifier consists of two bipolar junction transistors (BJTs) connected in a configuration that allows the current amplified by the first transistor to drive the second transistor. This arrangement results in a very high current gain, as the output current of the first transistor becomes the input current for the second. The input signal is applied to the base of the first transistor, which greatly amplifies it before passing it to the base of the second transistor for further amplification. The overall effect is a significant increase in both current and voltage gain, making it useful in various applications where high gain is required.