the magical number is .6v
The cutoff region is when the transistor doesn't have sufficient base current to drive a larger current from emitter to collector. Therefore, the transistor does not turn on and stays shut off.
A simple test to determine if a transistor is in cutoff or saturation is to measure the voltage across the collector-emitter (V_CE) terminal. If V_CE is close to the supply voltage, the transistor is likely in cutoff, indicating it is off. Conversely, if V_CE is very low (typically below 0.3V for a silicon transistor), the transistor is in saturation, meaning it is fully on and allowing maximum current to flow.
For switching applications transistor is biased to operate in the saturation or cutoff region. Transistor in cutoff region will act as an open switching whereas in saturation will act as a closed switch.
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 transistor the heat is created during transition stage means from cutoff to saturation and reverse, so if transistor used for high frequency application power loss can be minimized. The heat produced during switching is actually power loss.
When both junctions of an NPN transistor are reverse biased, the transistor is in the cutoff mode. In this mode, the transistor is effectively turned off, and it does not conduct current between the collector and emitter. As a result, the transistor behaves like an open switch, preventing current flow in the circuit.
Emitter, Collector and Base cutoff region, saturation region, and liner region
we will operate transistor mainly in 4 regions..namely active ,cutoff,saturation and pinch off region depending on the type of biasing. if it is under active region then transistor is a linear device.. linearity in the sense if the output is proportional to input then it is said to be linear.
The turn-on time in a bipolar junction transistor (BJT) refers to the duration it takes for the transistor to switch from the cutoff region (off state) to the saturation region (on state) after a forward bias is applied. Conversely, the turn-off time is the time required for the BJT to switch from saturation back to cutoff after the bias is removed. These times are influenced by factors such as the transistor's internal capacitances, the base drive current, and the collector-emitter voltage. Minimizing these times is crucial for improving the switching speed in high-frequency applications.
It won't work.
The beta cut off frequency is the frequency at which the current amplification of an amplifier transistor drops to three decibels below its value at 1 kilohertz. This is used in electronic engineering.
Transistor amplify and switch electrical power and electronic signals. These are made of semiconductor material with three or more terminals used to connect to an external circuit.