Mell When both junctions be and BC are reversed biased the transistor act as?
If BE is reverse biased and BC is forward biased, then it still acts like a transistor, but because of the physical way bjt’s are setup, you have much less gain than forward active. What would happen to a BJT if both junctions of the transistor are forward biased?
How the two junctions are are biased?
For a transistor to function, the two PN junctions must be properly biased. The base-emitter junction behaves like any other PN junction when viewed alone. If the base-emitter junction is forward biased, the transistor is on. If it is reverse biased, the transistor is off.
What makes a PN junction diode reverse biased?
Reverse-biased pn junction diode A pn-junction diode is said to be reverse biased when the positive terminal of a cell or battery is connected to the n-side of the junction and the negative terminal to the p-side. When reverse biased, the depletion region widens and the potential barrier is increased.
What kind of bias does a NPN transistor need?
NPN transistor needs both the reverse and forward bias for working. The forward bias is established between the Emitter voltage and the emitter. The reverse bias is connected between the collector voltage and the collector.
What happens when both junctions are connected in reverse bias?
When both junctions are connected in reverse bias, the transistor behaves as an open circuit or OFF switch. In this condition, the input voltage or the base voltage is zero. Therefore, the entire Vcc voltage appears across the collector. But, because of the reverse bias of the collector-emitter region, the current cannot flow through the device.
How is the bias voltage of a diode related to the barrier potential?
Notice that the negative side of Vbias is connected to the n region of the diode and the positive side is connected to the p region. This is one requirement for forward bias. A second requirement is that the bias voltage, Vbias, must be greater than the barrier potential of diode.