voltage regulator using op

Topics: Voltage regulator, Direct current, Integrated circuit Pages: 10 (906 words) Published: May 9, 2014
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ANALOG CIRCUIT DESIGN

VOLTAGE REGULATOR USING OP-AMP
PROJECT REPORT

By
T.SAI KUMAR (12BEC0116)
S.GIRISH(12BEC0253)
K.VISHWANATH(12BEC0459)
V.KARTHIK(12BEC0440)

VOLTAGE REGULATOR USING OP-AMP

ABSTRACT
In real life situations, we come across many scenario where we require a constant output voltage even though the input voltage is varying randomly .Voltage regulator is the device which produces constant output voltage for varying input. Generally in many of the household appliances like TV, refrigerator uses stabilizers to supply constant voltage to the appliance in spite of the fluctuations in input voltage. In this, we are going to explain the working of a voltage regulator using IC748 and transistors, resistors and capacitors.

INTRODUCTION
In most of the practical situations, the output of some systems required to be maintained at a constant level. So a voltage regulator serves the purpose. A voltage regulator is designed to automatically maintain a constant voltage  level. A voltage regulator may be a simple “feed forward” design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages. Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators  and central power station generator plants, voltage regulators control the output of the plant. In an electric power distribution  system, voltage regulators may be installed at a substation or along distribution lines so that all customers receive steady voltage independent of how much power is drawn from the line. Here in this circuit we are constructing a circuit using op-amp and transistors.

COMPONENTS REQUIRED

1)µA 741 op-amp
2)Transistor(2N3055)
3)Zener diode
4)Potentiometer
5)Resistors(100Ω,470Ω,6.8kΩ,3.3kΩ)
6)Capacitors(100µF,10µF)

CIRCUIT DIAGRAM

IC 741 DESCRIPTION
An operational amplifier (op-amp) is a DC coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op-amp produces an output potential (relative to circuit ground) that is typically hundreds of thousands of times larger than the potential difference between its input terminals. Operational amplifiers had their origins in analog computers, where they were used to do mathematical operations in many linear, non-linear and frequency-dependent circuits. Characteristics of a circuit using an op- amp are set by external components with little dependence on temperature changes or manufacturing variations in the op-amp itself, which makes op-amps popular building blocks for circuit design.

CIRCUIT DESCRIPTION

Many simple DC power supplies regulate the voltage using a shunt regulator such as a Zener diode, avalanche breakdown diode, or voltage regulator tube. Each of these devices begins conducting at a specified voltage and will conduct as much current as required to hold its terminal voltage to that specified voltage. The power supply is designed to only supply a maximum amount of current that is within the safe operating capability of the shunt regulating device (commonly, by using a series resistor). If the stabilizer must provide more power, the shunt regulator output is only used to provide the standard voltage reference for the electronic device, known as the voltage stabilizer. The voltage stabilizer is the electronic device, able to deliver much larger currents on demand. SERIES REGULATOR CIRCUIT

Control element in series with load between input and output. Output sample circuit senses a change in output voltage
Error detector compares sample voltage with reference voltage → causes control element to compensate in order to...