Quick answer: What Is The Cutoff Region?

Which transistor is best for switching?

Best Transistors: BJTs#1 NPN – 2N3904.

You can find most often NPN Transistors in low-side switch circuits.

#2 PNP – 2N3906.

For high-side switch circuits, you need a PNP style BJT.

#3 Power – TIP120.

#4 N-Channel (Logic Level) – FQP30N06L..

What devices use transistors?

By far the most common application of transistors today is for computer memory chips—including solid-state multimedia storage devices for electronic games, cameras, and MP3 players—and microprocessors, where millions of components are embedded in a single integrated circuit.

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.

Can a transistor base emitter junction be used as Zener diode?

The base-emitter or base-collector junction of a silicon transistor can be used as a simple diode or rectifier, or as a zener diode by using it in the appropriate polarity.

How do you tell if a transistor is on or off?

To find out which mode a PNP transistor is in, reverse all of the < and > signs. For example, to put a PNP into saturation VC and VE must be higher than VB. You pull the base low to turn the PNP on, and make it higher than the collector and emitter to turn it off.

How do you know if a transistor is in active mode?

Typically we want to have a transistor to operate in what is called active mode. Active mode is when the Base-Emitter junction is forward biased and the Base-Collector Junction is Reverse biased. For the npn this means that the Base has a higher potential than the Emitter and a lower potential than the collector.

What is the cutoff region of a transistor?

Whenever we observe the terminals of a BJT and see that the emitter-base junction is not at least 0.6-0.7 volts, the transistor is in the cutoff region. In cutoff, the transistor appears as an open circuit between the collector and emitter terminals.

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 cutoff current?

Collector Cutoff Current – ICEx or ICEv Collector cutoff current is the IC that still flows when the specified VC and a specified reverse bias is applied. It is normally less than either ICEO or ICER (collector current with the base open, or with the base resistively connected to the emitter).

When would you use a transistor?

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 base voltage is present, the switch is on.

What is quiescent operating point?

The operating point of a device, also known as a bias point, quiescent point or Q-point, is the steady-state DC voltage or current at a specified terminal of an active device such as a transistor with no input signal applied.

What is knee voltage?

The forward voltage at which the flow of current during the PN Junction begins increasing quickly is known as knee voltage. This voltage is also known as cut-in voltage. This voltage is the least reverse voltage at which the PN Junction can behave without harm to the current.

What is saturation region?

Saturation region This is the region in which transistor tends to behave as a closed switch. The transistor has the effect of its collector and Emitter being shorted. The collector and Emitter currents are maximum in this mode of operation.

What is active saturation and cutoff region?

The region between cut off and saturation is known as active region. In the active region, collector-base junction remains reverse biased while base-emitter junction remains forward biased. Consequently, the transistor will function normally in this region.

Why is emitter always forward biased?

When the base emitter junction is forward biased and the collector/base junction is reverse biased, the electrons move from the n-type region towards the p-type region and the holes move towards the n-type region. When they reach each other they combine enabling a current to flow across the junction.

What is cut off current in fuse?

General. A current-limiting fuse is a fuse which interrupts current in its current-limiting range by sensing actual current and fusing at a prescribed current flow. Modern current-limiting fuses offer protection by being able to cut-off fault currents before damaging magnitudes are reached.

What is the active region of a transistor?

The region between cut off and saturation is known as active region. In the active region, collector-base junction remains reverse biased while base-emitter junction remains forward biased. Consequently, the transistor will function normally in this region.

What is iC saturation?

Deep saturation region: 0.1 < vCE < 0.3 V (Si) or vCE≈ 0.2 V = Vsat (Si), iC is smaller than its active-mode level (iC < β iB). o Called saturation as iC is set by outside circuit & does not respond to changes in iB. 3.

How do you know if a BJT is in saturation?

How to know if a Transistor is Saturated – Through Actual Testing. You can conclude the operation of a transistor if it is saturated or not by doing actual measurement. Monitor the collector-emitter voltage of your circuit with a DMM. If the reading is below 0.3V, the transistor is at saturation.

How do you know if a transistor is NPN or PNP?

Steps to identify the NPN type transistor:Keep the Multimeter in the Diode mode.Keep the positive probe to the center pin (Base) of the transistor.Touch the negative probe to the pin-1 (Emitter). … Similarly touch the negative probe to the pin-3 (collector) with respect to the pin-2.More items…•