project presentation
DESCRIPTION
Our 4th Semester Project PresentationTRANSCRIPT
12/17/2008
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M. Raghib MalikM. Yasir Jamil KhanMunir Shah
B.E Electronics IVB.E Electronics IVB.E Electronics IVB.E Electronics IV
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An
Introduction to
555
Timer/Oscillator I.C
Backbone Of Modern Electronics
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“A semiconductor device that controls
various modes of on/off states
in electrical systems or circuits. The 555
timer is one of
the most widely used types of integrated
circuits.”
� First introduced around 1971
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Energy storage,
Periodic Waveforms, and
One of the most useful electronic devices
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� Pendulum� Bouncing ball� Vibrating string (stringed instrument)� Circular motion (wheel)� Cantilever beam (tuning fork)
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Three Three Three Three operating modesoperating modesoperating modesoperating modes
Monostable mode: The 555 functions as a "one-shot".
Applications include
�Timers
�Missing pulse detection
�Bounce free switches
�Touch switches
�Frequency Divider
�Capacitance Measurement, etc.
1.1.1.1.
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Astable Free Running mode: as an oscillator.
Uses include
�LED and lamp flashers
�Pulse generation
�Logic clocks
�Tone generation
�Security alarms, etc.
2.2.2.2.
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3.3.3.3.
Bistable mode or Schmitt trigger:
Operate as a flip-flop,
If the DIS pin is not connected and no capacitor is used.
Uses include
�Bounce free latched switches, etc.
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Inside a 555 Timer/Oscillator
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Different
Packages
of
555
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40 LED Bicycle Light
Our ProjectOur ProjectOur ProjectOur Project
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Transistors:
•2N2219A (high speed switches)
The 2N2219A and 2N2222A are silicon planar
Epitaxial NPN transistors. They are designed for
high speed Switching application at collector
current up to 500ma
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•2N2907A(General Purpose Amplifiers and switches):
The 2N2905A and 2N2907A are silicon planar
epitaxial PNP transistors designed for high
speed saturated switching and general
purpose applications
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