Introduction to Electronics & Communication Module-1
BMS INSTITUTE OF TECHNOLOGY AND MANAGEMENT
Doddaballapur Main Road. Avalahalli, Yelahanka. Bengaluru-560064.
Course Name: Introduction to Electronics Engineering Course Code: AY:2022-2023
22ESC143
Course Coordinator: Dr. Sumathi M.S.
Syllabus:
Power Supplies – Block diagram, Half-wave rectifier, Full-wave rectifiers and filters, Voltage
regulators, Output resistance and voltage regulation, Voltage multipliers. Amplifiers – Types of
amplifiers, Gain, Input and output resistance, Frequency response, Bandwidth, Phase shift,
Negative feedback, multi-stage amplifiers
Learning Outcome:
CO1: Analyze the working of various electronic circuits such as Power supplies and Amplifiers.
Page 1
,Introduction to Electronics & Communication Module-1
1.1 Power supplies - Block diagram
A regulated power supply ensures that the output current remains constant, even if the input
changes, by converting unregulated AC (alternating current) to a constant DC (direct current). The
block diagram of a D.C power supply is shown in Fig. 1.1.
Figure 1.1 Block diagram of a D.C power supply
• The mains input is at a relatively high voltage; a step-down transformer of appropriate turns ratio
is used to convert this to a low voltage.
• The a.c. output from the transformer secondary is then rectified using conventional silicon
rectifier diodes to produce an unsmoothed (or pulsating d.c.) output.
• This is then smoothed and filtered before being applied to a circuit which will regulate (or
stabilize) the output voltage so that it remains relatively constant in spite of variations in both
load current and incoming mains voltage.
• Fig. 1.2 shows the realization of the block diagram of a D.C power supply using the electronic
components in Fig. 1.1.
Figure 1. 2 Block diagram of a D.C power supply showing principal components
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, Introduction to Electronics & Communication Module-1
• The iron-cored step-down transformer feeds a rectifier arrangement.
• The output of the rectifier is then applied to a high-value reservoir capacitor. This capacitor stores
a considerable amount of charge and is being constantly topped-up by the rectifier arrangement.
The capacitor also helps to smooth out the voltage pulses produced by the rectifier.
• Finally, a stabilizing circuit (often based on a series transistor regulator and a Zener diode voltage
reference) provides a constant output voltage.
1.2 Rectifiers:
• Rectifiers are the circuits which converts a.c voltage to pulsating d.c voltage.
• Rectifiers can be grouped into two types:
i) Half-wave Rectifier
ii) Full-wave Rectifier
1.2.1 Half-wave Rectifier
• The simplest form of rectifier circuit makes use of a single diode and, since it operates on only
either positive or negative half-cycles of the supply, it is known as a half-wave rectifier. Fig. 1.3
shows a simple half- wave rectifier circuit.
Figure 1.3 A simple half-wave rectifier circuit
• The mains voltage (220 to 240 V) is applied to the primary of a step- down transformer (T1).
• The secondary of T1 steps down the 240 V r.m.s. to 12 V r.m.s.
• During positive half cycle, the diode D1 is forward biased and acts as a closed switch as shown in
figure 1.4, thus diode allows the current flows
Page 3
BMS INSTITUTE OF TECHNOLOGY AND MANAGEMENT
Doddaballapur Main Road. Avalahalli, Yelahanka. Bengaluru-560064.
Course Name: Introduction to Electronics Engineering Course Code: AY:2022-2023
22ESC143
Course Coordinator: Dr. Sumathi M.S.
Syllabus:
Power Supplies – Block diagram, Half-wave rectifier, Full-wave rectifiers and filters, Voltage
regulators, Output resistance and voltage regulation, Voltage multipliers. Amplifiers – Types of
amplifiers, Gain, Input and output resistance, Frequency response, Bandwidth, Phase shift,
Negative feedback, multi-stage amplifiers
Learning Outcome:
CO1: Analyze the working of various electronic circuits such as Power supplies and Amplifiers.
Page 1
,Introduction to Electronics & Communication Module-1
1.1 Power supplies - Block diagram
A regulated power supply ensures that the output current remains constant, even if the input
changes, by converting unregulated AC (alternating current) to a constant DC (direct current). The
block diagram of a D.C power supply is shown in Fig. 1.1.
Figure 1.1 Block diagram of a D.C power supply
• The mains input is at a relatively high voltage; a step-down transformer of appropriate turns ratio
is used to convert this to a low voltage.
• The a.c. output from the transformer secondary is then rectified using conventional silicon
rectifier diodes to produce an unsmoothed (or pulsating d.c.) output.
• This is then smoothed and filtered before being applied to a circuit which will regulate (or
stabilize) the output voltage so that it remains relatively constant in spite of variations in both
load current and incoming mains voltage.
• Fig. 1.2 shows the realization of the block diagram of a D.C power supply using the electronic
components in Fig. 1.1.
Figure 1. 2 Block diagram of a D.C power supply showing principal components
Page 2
, Introduction to Electronics & Communication Module-1
• The iron-cored step-down transformer feeds a rectifier arrangement.
• The output of the rectifier is then applied to a high-value reservoir capacitor. This capacitor stores
a considerable amount of charge and is being constantly topped-up by the rectifier arrangement.
The capacitor also helps to smooth out the voltage pulses produced by the rectifier.
• Finally, a stabilizing circuit (often based on a series transistor regulator and a Zener diode voltage
reference) provides a constant output voltage.
1.2 Rectifiers:
• Rectifiers are the circuits which converts a.c voltage to pulsating d.c voltage.
• Rectifiers can be grouped into two types:
i) Half-wave Rectifier
ii) Full-wave Rectifier
1.2.1 Half-wave Rectifier
• The simplest form of rectifier circuit makes use of a single diode and, since it operates on only
either positive or negative half-cycles of the supply, it is known as a half-wave rectifier. Fig. 1.3
shows a simple half- wave rectifier circuit.
Figure 1.3 A simple half-wave rectifier circuit
• The mains voltage (220 to 240 V) is applied to the primary of a step- down transformer (T1).
• The secondary of T1 steps down the 240 V r.m.s. to 12 V r.m.s.
• During positive half cycle, the diode D1 is forward biased and acts as a closed switch as shown in
figure 1.4, thus diode allows the current flows
Page 3
