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Calculate the DC base current of a transistor circuit if the DC collector current is 4.9mA and the DC emitter current is 5mA?
Wiki User
∙ 14y ago
Emitter current can be summed up by the formula:
IE = IC+ IB
Where IE = Emitter Current, IC = Collector Current, and IB = Base Current
So simply take IE - IC and you'll get an IB of about 100uA. (5mA-4mA = .1mA or 100uA)
Also, remember that IB controls IC and IE, not the other way around. You can also determine IB if Beta is known by the formula:
IC = IB * Beta
Which can be manipulated to equal IB = IC/Beta
Hope this was helpful.
Wiki User
∙ 14y ago
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What percentage of the total current in a transistor flows through the collector?
The total current in a transistor is the emitter current, which is the sum of the collector current and the base current. The ratio of collector current over base current, in linear mode, is beta-DC, or hFe. However, in order for linear mode to be true, the ratings of the transistor must not be exceeded, and the collector current must not be limited by the circuit. Note also that hFe is temperature dependent, and is expressed in the data sheet as a minimum, not an absolute value - it can vary from transistor to transistor.
What is the difference between common base emitter transistor and common base transistor?
Common base transistor if the emitter is open current Ie=0 but a small collector current thus exist.this current is reversed biased collector to the base voltage it is represented by Icbo while common emitter is d base terminal is open circuit and the base junction is reversed biased current Icbo flow from the tcollector to the emitter in the external circuit this current is called leakage current.
What is the Effect of collector resistance in emitter follower circuit?
Colector resistance in an emitter follower circuit serves to place a limit on how much current can be supplied by the transistor. Often, the resistor is sized so that a short circuit in the load does not cause the transistor to fail.
What happens when emitter and collector of a transistor are short?
The transistor acts like a normal pn diode. in NPN transistor the both n i.e.,collector and emitter ane shorted then they become a n and other is p so pn diode is formed. When the emitter and the collector of a transistor are short, the emitter current =the collector current.
What are the parameters of a transistor?
# parameter are usually the base current ib,collector current ic,emitter current ie,collector emitter voltagevce,base emitter voltagevbe,collector base voltagevcb which decide the operation &output of the transistor
What percentage of the total current in a transistor flows through the collector?
The total current in a transistor is the emitter current, which is the sum of the collector current and the base current. The ratio of collector current over base current, in linear mode, is beta-DC, or hFe. However, in order for linear mode to be true, the ratings of the transistor must not be exceeded, and the collector current must not be limited by the circuit. Note also that hFe is temperature dependent, and is expressed in the data sheet as a minimum, not an absolute value - it can vary from transistor to transistor.
What is the difference between common base emitter transistor and common base transistor?
Common base transistor if the emitter is open current Ie=0 but a small collector current thus exist.this current is reversed biased collector to the base voltage it is represented by Icbo while common emitter is d base terminal is open circuit and the base junction is reversed biased current Icbo flow from the tcollector to the emitter in the external circuit this current is called leakage current.
What is the Effect of collector resistance in emitter follower circuit?
Colector resistance in an emitter follower circuit serves to place a limit on how much current can be supplied by the transistor. Often, the resistor is sized so that a short circuit in the load does not cause the transistor to fail.
What cause transistor collector current to increase when its warming up?
The forward current of any semiconductor device is dependent on temperature. This can cause collector current to increase in an uncompensated circuit. In the worst case, this can cause thermal runaway, and failure of the device. Often, we compensate for temperature by placing biasing limits on the demand for the transistor's gain.
What happens when the base current of a transistor is decrease?
in a properly biased transistor, collector and emitter current also decrease
What happens when emitter and collector of a transistor are short?
The transistor acts like a normal pn diode. in NPN transistor the both n i.e.,collector and emitter ane shorted then they become a n and other is p so pn diode is formed. When the emitter and the collector of a transistor are short, the emitter current =the collector current.
What happens when collector and base of a transistor are short?
this transistor is common emitter configurated transistor nd if emmiter nd collector both terminals are reversed bias then no current will be flowing through th terminal...
What are the parameters of a transistor?
# parameter are usually the base current ib,collector current ic,emitter current ie,collector emitter voltagevce,base emitter voltagevbe,collector base voltagevcb which decide the operation &output of the transistor
Is active is a cutoff region of transistor?
The active region of a transistor is when the transistor has sufficient base current to turn the transistor on and for a larger current to flow from emitter to collector. This is the region where the transistor is on and fully operating.
In a npn transistor does the collector current reach an upper limit as the base current gets smaller?
No. As base current decreases, so does collector current.
Why is the base of transistor made very thin?
Base of transistor is made thin just to get Collector current equal to Emitter current.
What is darlington configuaration?
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.
