1
SIDDHARTH INSTITUTE OF ENGINEERING & TECHNOLOGY:: PUTTUR
(AUTONOMOUS)
Siddharth Nagar, Narayanavanam Road – 517583
QUESTION BANK (DESCRIPTIVE)
Subject with Code: Analog Circuits (23EC0406)
Course & Branch: B.Tech.–EEE
Regulation: R23 Year & Sem: II-B.Tech.& II-Sem.
UNIT –I
Diode Clipping and clamping circuits
1a) Define clipper and list types. [2M]
. A clipper is an electronic circuit designed to prevent a signal from exceeding a
certain voltage level. It "clips" off portions of the input waveform without distorting
the rest of the signal.
Types:
1. Series Clipper
2. Shunt Clipper
3. Positive Clipper
4. Negative Clipper
5. Biased Clipper
b) List the applications of clampers. [2M]
1. Signal Level Shifting
2. Waveform Shaping
3. Voltage Multipliers
4. Audio and Video Systems
c) Discuss the need of biasing of a transistor. [2M]
The transistor in its active region, allowing it to amplify signals without distortion. If
biasing is not done correctly, the transistor may enter the cutoff or saturation region,
leading to improper amplification or switching failures. Additionally, biasing
stabilizes the transistor’s operation against changes in temperature or variations in
transistor parameters, ensuring consistent performance.
d) Define operating point. [2M]
The operating point of a transistor, also called the quiescent point (Q-point), is the
steady-state point on the transistor’s characteristic curves where it operates when no
input signal is applied.
e) What is thermal Runaway? [2M]
Thermal runaway is a condition in a transistor where an increase in temperature causes
an increase in collector current, which further increases the temperature, leading to
even more current and heat, and eventually damages or destroys the transistor.
2a) Explain positive and negative clippers with neat sketches [5M]
, 2
.
During the positive half of the input voltage, terminal A is positive with respect to B.
This reverse biases the diode and it acts as an open switch Therefore all the applied
voltage drops across the diode and none across the resistor As a result of this there is
no output voltage during the positive half cycle of the input voltage.
During the negative half cycle of the input voltage, terminal B is positive with respect
to A. Therefore it forward biases the diode and it acts as a closed switch. Thus there is
no voltage drop across the diode during the negative half cycle of the input voltage.
All the input voltage is dropped across the resistor as shown in the output waveform.
During the positive half cycle of the voltage, terminal A is positive with respect to
terminal B There for the diode is forward biased and it acts it as a closed switch As a
result, all the input voltage appears across the resistor. During the negative half cycle
of the input voltage, terminal B is positive with respect to the terminal A. Therefore
the diode is reverse biased and it acts as an open switch, Thus there is no voltage drop
across the resistor during the negative half cycle as shown in the output waveform.
b) Explain about positive biased clippers with neat sketches [5M]
During the positive half-cycle, when the input voltage is less than (V_bias +
0.7V) (for a silicon diode), the diode remains OFF, and the output follows the
input.
When the input voltage exceeds (V_bias + 0.7V), the diode turns ON and
conducts, shunting the extra voltage away, resulting in a clipped output.
During the negative half-cycle, the diode remains OFF, and the signal passes
unaffected.
, 3
a) Describe the operation of clipping at two independent levels [5M]
A parallel, a series, or a series-parallel arrangement may be used in double-ended
limiting at two independent levels. A parallel arrangement is shown in Figure 1, Figure
2 shows the transfer characteristic and the output for a sinusoidal input. The input-
output characteristic has two breakpoints, one at v0 = v, = VR1 and the second at v0 =
v, = -VR2 and has the following characteristics.
, 4
b) Draw the transfer characteristics of clippers and explain. [5M]
The transfer characteristic of a clipper circuit describes the relationship between the
input voltage and the output voltage, showing how the circuit clips or limits the input
signal. Generally, a clipper's transfer characteristic will have a linear region where the
output follows the input, and a flat region where the output is clamped at a specific
voltage level, indicating that the input signal is being clipped.
SIDDHARTH INSTITUTE OF ENGINEERING & TECHNOLOGY:: PUTTUR
(AUTONOMOUS)
Siddharth Nagar, Narayanavanam Road – 517583
QUESTION BANK (DESCRIPTIVE)
Subject with Code: Analog Circuits (23EC0406)
Course & Branch: B.Tech.–EEE
Regulation: R23 Year & Sem: II-B.Tech.& II-Sem.
UNIT –I
Diode Clipping and clamping circuits
1a) Define clipper and list types. [2M]
. A clipper is an electronic circuit designed to prevent a signal from exceeding a
certain voltage level. It "clips" off portions of the input waveform without distorting
the rest of the signal.
Types:
1. Series Clipper
2. Shunt Clipper
3. Positive Clipper
4. Negative Clipper
5. Biased Clipper
b) List the applications of clampers. [2M]
1. Signal Level Shifting
2. Waveform Shaping
3. Voltage Multipliers
4. Audio and Video Systems
c) Discuss the need of biasing of a transistor. [2M]
The transistor in its active region, allowing it to amplify signals without distortion. If
biasing is not done correctly, the transistor may enter the cutoff or saturation region,
leading to improper amplification or switching failures. Additionally, biasing
stabilizes the transistor’s operation against changes in temperature or variations in
transistor parameters, ensuring consistent performance.
d) Define operating point. [2M]
The operating point of a transistor, also called the quiescent point (Q-point), is the
steady-state point on the transistor’s characteristic curves where it operates when no
input signal is applied.
e) What is thermal Runaway? [2M]
Thermal runaway is a condition in a transistor where an increase in temperature causes
an increase in collector current, which further increases the temperature, leading to
even more current and heat, and eventually damages or destroys the transistor.
2a) Explain positive and negative clippers with neat sketches [5M]
, 2
.
During the positive half of the input voltage, terminal A is positive with respect to B.
This reverse biases the diode and it acts as an open switch Therefore all the applied
voltage drops across the diode and none across the resistor As a result of this there is
no output voltage during the positive half cycle of the input voltage.
During the negative half cycle of the input voltage, terminal B is positive with respect
to A. Therefore it forward biases the diode and it acts as a closed switch. Thus there is
no voltage drop across the diode during the negative half cycle of the input voltage.
All the input voltage is dropped across the resistor as shown in the output waveform.
During the positive half cycle of the voltage, terminal A is positive with respect to
terminal B There for the diode is forward biased and it acts it as a closed switch As a
result, all the input voltage appears across the resistor. During the negative half cycle
of the input voltage, terminal B is positive with respect to the terminal A. Therefore
the diode is reverse biased and it acts as an open switch, Thus there is no voltage drop
across the resistor during the negative half cycle as shown in the output waveform.
b) Explain about positive biased clippers with neat sketches [5M]
During the positive half-cycle, when the input voltage is less than (V_bias +
0.7V) (for a silicon diode), the diode remains OFF, and the output follows the
input.
When the input voltage exceeds (V_bias + 0.7V), the diode turns ON and
conducts, shunting the extra voltage away, resulting in a clipped output.
During the negative half-cycle, the diode remains OFF, and the signal passes
unaffected.
, 3
a) Describe the operation of clipping at two independent levels [5M]
A parallel, a series, or a series-parallel arrangement may be used in double-ended
limiting at two independent levels. A parallel arrangement is shown in Figure 1, Figure
2 shows the transfer characteristic and the output for a sinusoidal input. The input-
output characteristic has two breakpoints, one at v0 = v, = VR1 and the second at v0 =
v, = -VR2 and has the following characteristics.
, 4
b) Draw the transfer characteristics of clippers and explain. [5M]
The transfer characteristic of a clipper circuit describes the relationship between the
input voltage and the output voltage, showing how the circuit clips or limits the input
signal. Generally, a clipper's transfer characteristic will have a linear region where the
output follows the input, and a flat region where the output is clamped at a specific
voltage level, indicating that the input signal is being clipped.
