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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.
Most transistors and diodes exhibit reverse bias leakage.
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.
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 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
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.
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.
Icbo (collector to base current when emitter is open) also called reverse saturation current as Is in reverse bias p-n junction diode.Regards
Reverse bias
Most transistors and diodes exhibit reverse bias leakage.
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.
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.
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 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
reverse bias it
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
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.