Quick Answer: What Is Saturation And Cutoff In Transistors?

What is the cutoff region?

The Cutoff Region of a FET transistor is the region where the drain-source channel resistance is at its maximum and there is no no drain current, ID, flowing from the drain to the source of the FET transistor.

In this region, the transistor is off..

What is cut off and saturation region?

In cutoff, the transistor appears as an open circuit between the collector and emitter terminals. In the circuit above, this implies Vout is equal to 10 volts. The second region is called “saturation”. This is where the base current has increased well beyond the point that the emitter-base junction is forward biased.

Why is emitter always forward biased?

Why emitter is always forward biased? Emitter is always forward biased w.r.t base so as to supply majority charge carriers to the base.

How do you know if a transistor is saturated?

Monitor the collector-emitter voltage of your circuit with a DMM. If the reading is below 0.3V, the transistor is at saturation. Transistors are having saturation voltage range from 0.7V and below but for a circuit designed for hard saturation, the VCE will be lower.

Why is VBE 0.7 V?

For an unbiased transistor, considering only the BE junction which is a pn junction diode, 0.7V is the potential barrier. In an npn transistor base is positive(p) and emitter is negative(n). … But in a pnp transistor the base is negative(n) and emitter is positive(p) so the vbe=-0.7V.

What is hard saturation?

Hard saturation is when the transistor operates in the saturation region under all operating conditions. Remember that the current gain changes as the operating conditions such as temperature, and collector current, change.

What is saturation in transistor?

Saturation is the on mode of a transistor. A transistor in saturation mode acts like a short circuit between collector and emitter. In saturation mode both of the “diodes” in the transistor are forward biased. That means VBE must be greater than 0, and so must VBC.

What is cut off region in transistor?

It is a region in which transistor remains OFF and needed some threshold voltage to operate or to move in active region. If the emitter base terminal is reverse biased and base collector terminal is also reverse biased ; we can say Transistor is in Cutoff region.

When the transistor is in saturation the collector to emitter voltage?

When the transistor operates in the Saturation then the voltage between collector and emitter terminal (Vce) is very low (typically it is 0.1 to 0.2 V), and the collector current Ic is maximum.

Is VBE always 0.7 V?

VBE is the voltage that falls between the base and emitter of a bipolar junction transistor. VBE is approximately 0.7V for a silicon transistor. For a germanium transistor (which is more rare), VBE is approximately 0.3V. Again, this formula, can be used for either silicon or germanium transistors.

What is PNP bipolar transistor?

Definition: The transistor in which one n-type material is doped with two p-type materials such type of transistor is known as PNP transistor. It is a current controlled device. The small amount of base current controlled both the emitter and collector current.

What is the saturation voltage?

saturation voltage, collector-emitter (VCE(sat)) The voltage between the collector and emitter terminals under conditions of base current or base-emitter voltage beyond which the collector current remains essentially constant as the base current or voltage is increased. (Ref.

What bias conditions must exist for a transistor to operate in cutoff?

When the emitter junction is forward biased and the collector junction is forward biased, the transistor operates in saturation region. When the emitter junction is reverse biased and the collector junction is reverse biased, the transistor operates in cutoff region.

Why VCE SAT is 0.2 V?

Because the charge carriers injected from the base effectively eliminate the depletion zone between the collector and emitter. The collector current doesn’t have to overcome the P-N junction potential because the base current has neutralized it.

What do you mean by saturation?

saturation. Saturation means holding as much moisture as possible. When you water your houseplants, you may soak them until the soil around each plant reaches saturation. The noun saturation means the act of completely soaking something until it’s absorbed as much water as it can.