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To reverse bias a base-collector junction in a bipolar junction transistor (BJT), you need to apply a positive voltage to the collector relative to the base for an NPN transistor (or a negative voltage for a PNP transistor). This involves connecting the collector terminal to a higher potential and ensuring the base terminal is at a lower potential. As a result, the depletion region at the base-collector junction widens, preventing current flow between the collector and base. This condition is essential for transistor operation in certain configurations, such as in cutoff mode.
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Why a transistor can be operated in active region?
a transistor can only work in active region cox in active region collector base junction is in reverse bias and emitter base junction is in forward bias.
When emitter is open and the collector junction is reverse biased still a very small current flows in the circuit why?
Most transistors and diodes exhibit reverse bias leakage.
What will happen if emitter base is reversed bias and collector base is forward bias?
If emitter-base is reverse biased then there will be no amplification effect on collector-emitter. If collector-base is forward biased, it will act like a diode, but without emitter-base current, that is meaningless.
Why do you have to connect a resistor to collector of transistor?
Type your answer here... to properly bias the junction for current flow thru the transistor. The voltage potential must be different on the base than the collector
Forward bias and reverse bias?
forward bias is in the direction a junction or vacuum tube wants to conduct currentreverse bias is in the direction a junction or vacuum tube opposes conducting current
What bias conditions must be present for the normal operation of a transistor ampilifier?
Assuming you mean a bipolar junction transistor (BJT): 1. Reverse bias on the collector-base junction. 2. Forward bias on the base-emitter junction, that is 3. Sufficient to give the correct operating point of collector voltage/collector current.
Why a transistor can be operated in active region?
a transistor can only work in active region cox in active region collector base junction is in reverse bias and emitter base junction is in forward bias.
What is Icbo in transistors?
Icbo (collector to base current when emitter is open) also called reverse saturation current as Is in reverse bias p-n junction diode.Regards
What are the bias conditions base collector junctions for a transistor to operate as a switch?
Reverse bias
When emitter is open and the collector junction is reverse biased still a very small current flows in the circuit why?
Most transistors and diodes exhibit reverse bias leakage.
What is the deffbetween forward and reverse biased?
Asking about biasing of the emitter alone does not make sense. When you talk about bias, you talk about a junction, such as emitter-base or emitter-collector or base-collector. In a bipolar junction transistor (BJT) both the emitter-base and emitter-collector need to be forward biased, otherwise you are operating the BJT in cutoff mode. Certainly, if you intend to operate the BJT as a switch, then reverse bias for emitter-base (actually, zero bias) could well be one of the valid states, corresponding to a cutoff condition for emitter-collector. However, operation in linear mode, the other normal way to use a BJT, requires that both the emitter-base and the emitter-collector be forward biased. Of course, depending on the ratio of emitter-base to emitter-collector versus hFe, you could also be saturated, which is a non-linear mode, i.e. an on switch.
What will happen if emitter base is reversed bias and collector base is forward bias?
If emitter-base is reverse biased then there will be no amplification effect on collector-emitter. If collector-base is forward biased, it will act like a diode, but without emitter-base current, that is meaningless.
Why do you have to connect a resistor to collector of transistor?
Type your answer here... to properly bias the junction for current flow thru the transistor. The voltage potential must be different on the base than the collector
Forward bias and reverse bias?
forward bias is in the direction a junction or vacuum tube wants to conduct currentreverse bias is in the direction a junction or vacuum tube opposes conducting current
How can a p-n junction act as a capacitor?
reverse bias it
Why emitter base junction is always forward biased for normal operation of transistor?
The easy answer - it's not always forward biased. Both it, and the collector-base junction, must be forward biased to pass current through to the collector. Whether NPN or PNP the relative bias (voltage) on the base determines the conduction from emitter to collector. NPN: if the base is positive, relative to the collector and emmiter, the transistor conducts. PNP: if the base is negative, relative to the collector and emmitter, it conducts. For either transistor arrangement, draw two diodes connected either by their anodes or by their cathodes. The base is the region between them. In an NPN, a positive voltage on the anode, compared the to the cathode(s), will forward bias both, allowing current to flow. The same applies to a PNP with a relative negative voltage being the 'switch', turning both on. bob 02/07/2009 The first paragraph is incorrect. The collector-base junction will be reverse biased for normal operation. The only time an NPN base will be biased more positively than the collector is when it's operating in saturation mode. The second paragraph is also misleading. It implies that current flows (for NPN) from the collector to the base and then from the base to the emitter. Emitter current is base current plus collector current. The collector-base junction is normally reverse biased, so little current would flow. Here's a link with relevant info: http://www.nationmaster.com/encyclopedia/Bipolar-junction-transistors Dennis
What is ment by early effect in transistor?
For a fixed value of Vbe,as Vce increases the reverse bias on the collector base junction increases,hence the width of the depletion layer increases.therefore base width decreases,so collector current increases. To minimise this effect base must be heavily doped than collector CONSEQUENCES: ->due to early effect collector current increases with increasing Vce,for a fixed value of Vbe. ->the base current do not change significantly Early effect=collector current * correction factor
