Page 80 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Advantages of integrated circuits over discrete circuit (Refer Table 1)
Table 1

Integrated circuits Discrete circuits

1 All in a single chip All are separate discrete
components

2 Requires less space Requires more space
due to smaller size
3 Cheaper due to mass Costlier due to individual
manufacture components
4 More reliable due to Less reliable
specific construction
5 Easy for servicing and Difficult for servicing and
repairs repairs

1 ICs are manufactured Discrete devices can be
for specific applications used for any circuit
having specific circuits
2 If any part of IC is Only particular defective
defective, the entire component requires
IC is to be replaced replacement

When the advantages are considered, the disadvantages of IC are negligible. They are widely used for different
applications such as voltage regulators, audio amplifiers, TV circuits, computers, industrial amplifiers etc. ICs are
available in different pin configurations in different outlines suitable for different circuits.
Integrated circuit (IC) voltage regulators: The series voltage regulators discussed in earlier lessons are available
in the form of integrated circuits (ICs). They are known as voltage regulator ICs.
There are two types of voltage regulator ICs. They are,
– Fixed output voltage regulator ICs
– Adjustable output voltage regulator ICs.
Fixed output voltage regulator ICs: The latest generation of fixed output voltage regulator ICs have only three pins
as in Fig 1. They are designed to provide either positive or negative regulated DC output voltage.
These ICs consist of all those components and even more in the small packages in Fig 1. These ICs, when used
as voltage regulators, do not need extra components other than two small value capacitors as in Fig 2.
The reason behind using capacitor C1 is when the voltage regulator IC is more than a few inches from the filter
capacitors of the unregulated power supply, the lead inductance may produce oscillations within the IC. Capacitor
C1 prevents setting up of such oscillations. Typical value of bypass capacitor C1 range from 0.220µF to 1µF. It
is important to note that C1 should be connected as close to the IC as possible.

The capacitor C2 is used to improve the transient response of the regulated output voltage. C2 bypasses these
transients produced during the ON/OFF time. Typical values of C2 range from 0.1µF to 10µF.
Fixed voltage three terminal regulators are available from different IC manufacturers for different output voltages
(such as 5V, 9v, 12V, 24V) with maximum load current rating ranging from 100mA to more than three amps.

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CITS : Power - Electrician & Wireman - Lesson 60-69