THE 555 TIMER

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THE 555 TIMER
Presentation by Uma.S.V Lecturer,Dept. of
EC, R.N.S.I.T,Bangalore.
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THE 555 TIMER
The 555 timer is a Monolithic integrated circuit
timers generate precise time delays or timings
pulses whose duration or repetition rate is
determined by an external timing resistor R and
timing capacitor C
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Applications of 555 Timer Monostable Astable
Multivibrators Waveform generators Burglar
Alarms Measurement ,Process Control
Circuits Missing pulse detectors Traffic light
control Automatic Battery chargers Logic
probes DC to DC Converters etc.
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FEATURES OF 555 TIMER
1.The 555 Timer is a highly stable
inexpensive device for generating accurate
time delay or oscillation. 2.It can provide time
delays ranging from microseconds to
hours. 3.It can be used with power supply
voltage ranging from 5V to 18V.
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4.It can source or sink upto 200mA. 5.It is
compatible with both TTL CMOS logic
circuits. 6.It has very high temperature
stability it is designed to operate in the
temperature range -55o to 125oC.
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• 555 can have two major operating modes
• Monostable multivibrator
• Astable multivibrator

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THE 555 TIMER
8
Vcc
8
UC
Vref
4
6
S
Q
5
FF
LC
R
2
3
PA
7
1
9
Vcc
4
8
R
7
NE555
3
Output
6
2
C
5
1
555 As Monostable Multivibrator