Electronics - Bipolar Junction Transistors (BJT) - Discussion

Saturation and cutoff region transistors act as switches in switch condition is on and off. So it is used for digital circuits.

One of the most common uses for transistors in an electronic circuit is as simple switches. In short, a transistor conducts current across the collector-emitter path only when a voltage is applied to the base. When no base voltage is present, the switch is off. When the base voltage is present, the switch is on.

The areas of operation for a transistor switch are known as the Saturation Region and the Cut-off Region. And use the transistor as a switch by driving it back and forth between its "fully-OFF" (cut-off) and "fully-ON" (saturation) regions.

Digital circuits used for switching purpose thats why transistor works only in saturation and cutoff region.

For switching purpose transistor are used in saturation and cutoff. Whereas for amplification purpose transistor are used in active region.

But transistor is mostly used as an amplifier in active region of it.

Anybody tell me what is the significance of cut off region?

Cut off (no collector current), useful for switch operation.

What can we say about the voltages in cut off as well as saturation ? I mean when Ic is zero in cut off Vce should be maximum right?what about other voltages i.e. (base emitter and collector base) I know that base emitter junction will be reverse biased but can we come to know about the exact voltage? kindly guide me.

I just want to know the voltages in both the modes i.e. cutoff and saturation.

Digital system as very clear having two states namely high or low, saturation implies high state and cut off implies off state.