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. Note. We provide biasing to the transistor to ensure that it operates in the active region.
Is the transistor biased in the active region?
The collector to base feedback configuration ensures that
the transistor is always biased in the active region
regardless of the value of Beta (β). The DC base bias voltage is derived from the collector voltage V
C
, thus providing good stability.
How are transistors biased on?
Biasing is the process of providing DC voltage which helps in the functioning of the circuit. A transistor is based in order to make the
emitter base junction forward biased
and collector base junction reverse biased, so that it maintains in active region, to work as an amplifier.
How is PNP transistor biased to operate in the active mode?
Figure below shows both n-p-n and p-n-p transistors biased in the active mode of operation. To operate in active mode,
a transistor’s VBE must be greater than zero and VBC must be negative
. Thus, the base voltage must be less than the collector, but greater than the emitter. … Usually this voltage is usually around 0.6V.
What is active region of a transistor?
Active region is that
region in which the emitter base junction is forward biased while the collector base junction is reverse biased
.
Why are collectors reverse biased?
Collector is
always reverse-biased w.r.t base so as to remove the charge carriers from the base-collector junction
.
Which transistor is more stable?
In particular, the stability factor, which is a measure of the change in collector current with changes in reverse saturation current, is approximately β+1. To ensure absolute stability of the amplifier, a stability factor of less than 25 is preferred, and so
small-signal transistors
have large stability factors.
Can I use PNP instead of NPN?
Generally, the
PNP transistor can replace NPN
transistors in most electronic circuits, the only difference is the polarities of the voltages, and the directions of the current flow. PNP transistors can also be used as switching devices and an example of a PNP transistor switch is shown below.
Are NPN and PNP transistors interchangeable?
Answer: NPN and PNP transistors are
interchangeable
if you remember one simple rule: A bipolar transistor is essentially two back-to-back diodes with the base being the common connection. … On the left is an NPN (negative-positive-negative) transistor and on the right is a PNP (positive-negative-positive) transistor.
What is the symbol of PNP transistor?
| PNP Transistor NPN Transistor | Symbol | Collector -emitter voltage Negative Positive | Emitter arrow Pointed in Pointed out |
|---|
What is IC saturation?
Saturation, as the name might imply, is
where the base current has increased well beyond the point that the emitter-base junction is forward biased
. In fact, the base current has increased beyond the point where it can cause the collector current flow to increase.
How do you know if a transistor is active?
REVIEW: A transistor is said to be in its active mode
if it is operating somewhere between fully on (saturated) and fully off (cutoff)
. Base current regulates collector current. By regulate, we mean that no more collector current can exist than what is allowed by the base current.
What is the difference between BJT and FET?
The acronym of the BJT is Bipolar Junction Transistor and FET stands for Field Effect Transistor. … The major difference between BJT and FET is that
in a field-effect transistor only majority charge carries flows, whereas in BJT both majority and minority charge carriers flow.
Why emitter is forward biased?
Emitter is
always forward biased w.r.t base so as to supply majority charge carriers to the base
.
What is a reverse biased transistor?
If it is reverse biased,
the transistor is off
. This is just like a diode. If you forward bias a diode, the diode conducts. If you reverse bias the diode, the diode cuts off. Now, the base-emitter junction in a transistor is going to essentially turn the transistor on or off.
Why is emitter always forward biased?
Emitter is always forward biased
w.r.t base so as to supply majority charge carriers to the base
.
