2. Presentation
Name: Sharmin Akter Liza
Semester: 3rd
Id: 220311012
Batch: CSE-10th
Topics: BJT biasing, DC fixed bias,
emitter bias , voltage divider Bias,
collector feedback bias.
Subject: Electronic Devices &Circuits
Sub Code-EEE -212
To: Nigar Afsana
(Lecturer of EEE department)
3. What is BJT biasing?
**BJT means BipolarJunction Transistor.
**BJT biasing establishes the operating point of a bipolar junction transistor. It involves
applying appropriate voltages and currents to ensure the transistor operates within the
desired region. Common biasing configurations include fixed bias, collector feedback bias,
and emitter bias. Proper biasing is essential for optimal transistor performance.
Four types of biasing in BJT. They are-
1.Fixed bias.
2.Collector-to-base bias.
3.Fixed bias with emitter resistor.
4.Voltage divider bias or potential divider
e
BJT figure-01
4. DC fixed bias
DC fixed bias is a BJT biasing
configuration where a resistive
voltage divider is connected to the
base terminal. This establishes the
base bias voltage for the desired
collector current. It is simple but
less stable, as variations in
temperature and transistor
parameters can affect the bias
point.
5. What is Emitter bias?
Emitter bias involves placing a resistor in series with the emitter terminal of a
BJT. This configuration provides negative feedback, stabilizing the bias point and
compensating for variations in transistor parameters, ensuring stable operation
and allowing the transistor to function reliably in amplifier circuits.
6. Voltage Divider Bias
Voltage divider bias uses a resistive voltage divider connected from the supply
voltage to the base terminal of a BJT. This establishes a stable bias voltage, ensuring
proper operation and allowing the transistor to operate within the desired region for
amplification or switching applications.
The formula of voltage divider bias is VRx=Vin(RxRT) where Rx is the specific resistor
7. DC bias with voltage feedback
DC bias with voltage feedback involves using a voltage divider connected from
the collector to the base terminal of a BJT. This configuration stabilizes the
bias point by providing feedback to the base, compensating for variations in
transistor parameters and ensuring stable operation under different
conditions.
8. Collector Feedback Bias
Collector feedback bias uses a feedback resistor connected from the collector
to the base terminal of a BJT. This resistor stabilizes the bias point by
compensating for variations in transistor parameters, enhancing stability and
reducing sensitivity to temperature and transistor variations.
9. Thank you so much
For watching my presentation…….
