Integrated Circuits-Microprocessor
Microprocessor
is an example of integrated circuit. Integrated
Circuits
can be found in
digital clocks,
mobile phones and many other electronic devices. A
Simple circuit is made up of
diodes,
resistors
and transistors and an integrated circuit can be said as
combination of many other inbuilt circuits in one single
chip. Nowadays chip production is based on
photolithography.
Before
understanding the concept of Integrated Circuits we must
know what is a transistor. IC 's are made up of
transistors.
Transistors
A device
composed of semiconductor material that amplifies a
signal or opens or closes a circuit. Invented in 1947 at
Bell Labs, transistors have become the key ingredient of
all digital circuits, including computers. Today's
microprocessors contains tens of millions of microscopic
transistors. A Darlington pair is two transistors
connected together to give a very high current gain. A
transistor consists of three layers of silicon or
germanium semiconductor material. There are also Field
Effect Transistors which we call FETs but they are
different than bipolar junction transistors. We can
easily test a transistor through a multi meter. P is for
a positive charged layer and N is for a negative charged
layer in NPN and PNP Transistors.
Transistor Types
 
Integrated
circuits are used for a variety of devices, including
microprocessors,
audio and video equipments, and automobiles. Integrated
circuits are classified by the number of transistors and
other electronic components they contain:
SSI (small-scale integration): Up to 100 electronic
components per chip
MSI (medium-scale integration): From 100 to 3,000
electronic components per chip
LSI (large-scale integration): From 3,000 to 100,000
electronic components per chip
VLSI (very large-scale integration): From 100,000 to
1,000,000 electronic components per chip
ULSI (ultra large-scale integration): More than 1
million electronic components per chip
Remember these
points to integrate a circuit
or How to Solder
a Circuit
IC's can be
soldered directly into printed circuit boards, or may
put into sockets which have already been soldered into
the PCB.
When soldering, make sure that the socket is in the
accurate way round and that no pins have been bent
underneath the body.
When putting new IC's it is often necessary to bend the
pins in slightly, in order to fit it into the PCB.
Transistors
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Circuits
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