Wednesday, October 3, 2007

Working with IC555

IC555 is the most versatile chip and is used in all most every kind of application because of its multi functionaly. as we know its on chip multivibrator means with IC555 one can design astable, monostable, bistable multivibrator. its main application is to generate timings, clock waveform, generate synchronizing signals, used as square wave oscillator and many more.

so here we are going to discuss some of the applications of IC555. here you will not find a theory of IC555 that how does it work in astable or monostable operation as everybody is already familiar with that. but here there is a practical approach given to design various application of the chip.

Astable Multivibrator:-

for astable operation of IC555 we have two design equations

f = 1.44 / (R1+2*R2)*C and

% duty cycle = (R1+R2) / (R1+2*R2)

we have to find out three unknowns R1, R2 & C.

for given values of design parameters frequency and duty cycle we have to find out these three unknown. so lets understand it with one example. let's design 40KHz multivibrator for 60% duty cycle.

from given values

40000 = 1.44/(R1+2*R2)*C and

0.6 = (R1+R2) / (R1+2*R2)

here we have to assume the value of C. as from two equation we can not find three unknown. let us assume C=0.01 microF. substuting this value

(R1+2*R2) = 3600 substuting this value in second equation

(R1+R2) = 2160

from these two equations R1 = 720 ohm and R2 = 1.44K. the nearest practical values will be 780 ohm and 1.5K. putting these values we shall get freq = 38 KHz and duty cycle = 60%. if we use potentiometer of 4.7K instead of fixed value of R2 then we can set the exact 40 KHz freq.

if you want to design astable multivibrator for exact 50% dutycycle then the slight modification is done by connecting one diode accros registrer R2 as shown. now the value of both registers will be R1=R2=R and there is only one design equation

f = 1 / 0.69*R*C. here by assuming value of capacitor one can easily find the value of register. duty cycle will be always 50%. for above values of frequency and capacitor value of R will be 3.6K.

Monostable multivibrator:-

for monostable operation there is only one design equation

T = 1.1RC

this is the time for which the o/p remains high. if required time period is 1 ms. then

0.001 = 1.1RC here assume any suitable value of capacitor say 1 microF. so

R = 0.001 / 1.1*0.000001 = 990 ohm. if we take nearest value of 1K then time period will be 1.1ms.

Pulse Amplitude Modulation(PAM):-

IC555 can be configured to generate PAM with one NPN transistor connected at output. the chip is configured in astable mode to generate high freqency carrier wave probabely 100-500KHz. this output is fed to base of NPN transistor. the collector of transistor is coupled with low frequency information signal probabely audio signal. the output at the collector of transistor that you get is PAM wave. the amplitude of pulses generated by IC555 varies in accrodance with the instanteneous amplitude of information signal.

Pulse Width Modulation(PWM):-

if IC555 is configured in monostable and high frequency trigger is applied (10-20KHz) with modulating signal applied to control input the output from chip with be PWM wave in which width width of pulse varies as amplitude of modulating wave changes. the capacitor and diode connected before control i/p to provide proper DC shift to i/p wave. internally the control voltage will change the reference voltage of comparator so charging time of capacitor changes every time so width of o/p pulse also changes.

Pulse Position Modulation (PPM):-

again IC555 is configured in astable mode(to generate carrier wave) and modulating wave is applied to control i/p via capacitor diode circuit. the output from chip will be PPM wave. the control i/p will change the position of pulse as the amplitude of modulating wave changes.

18 comments:

Anonymous said...

how can i generat 500 KHZ from IC555

Anonymous said...

This post presents clear idea in favor of the new visitors
of blogging, that actually how to do blogging.
See this: zobacz, http://abeyance.
katowice.pl

Anonymous said...

It's very straightforward to find out any matter on net as compared to textbooks, as I found this paragraph at this site.
See this: zobacz, http://mass-effect.com.pl

Anonymous said...

Hi! I simply wish to offer you a big thumbs up for your excellent info you have right here on this post.

I will be coming back to your site for more soon.

Also visit my web-site: kliknij

Anonymous said...

My brother rеcommendеԁ I
might lіke thiѕ website. Hе wаs tоtally right.
This post actually mаde my daу. You сan not imagine
simplу hoω much tіme I had ѕpent
for thіs info! Thanks!

Heгe is my homеpage; Research.Calit2.Net

Anonymous said...

It's an amazing piece of writing designed for all the internet viewers; they will get benefit from it I am sure.

Visit my webpage; Resistor Resistance

Anonymous said...

What i don't understood is if truth be told how you're nοt reallу a lot
moге neаtly-lіked than you may be rіght now.
You're very intelligent. You realize therefore considerably when it comes to this matter, produced me personally consider it from a lot of numerous angles. Its like men and women don't ѕeеm to be іntеresteԁ unleѕs іt іѕ one thing
tо аccomplish wіth Lаdy gаga!

Your own stuffs great. Alwaуs maintain it up!


Also ѵiѕit my blοg ρost: varistors

Anonymous said...

Αw, this was аn еxtremely gooԁ post.

Sρenԁing some time anԁ actuаl effort tο crеаte a gοod aгticle… but what can I say… I hesitatе a
lot and never manage tο gеt anything donе.


Feel free to surf to mу ωеbpagе .
.. potmeter

Anonymous said...

I think the аdmin of this ωeb site is in fact working harԁ in favor of his website,
for the reason thаt herе еvеrу informatіon is quality based materіal.



Herе is my weblоg Wire Wound Resistor

Anonymous said...

Thіs article pгovidеs cleaг idea
in support of the new users of bloggіng, thаt really how to do bloggіng.


my ωeb pаge: Resistor resistance

Anonymous said...

Hі there! I unԁеrѕtand this is somewhat off-topic
but I had to ask. Does building a well-еstablishеd webѕite such аѕ yours гequire a lot of woгκ?
I'm brand new to blogging but I do write in my journal daily. I'd like
to start a blog so I ωill be able to
sharе my personal expeгience and thoughtѕ online.
Pleaѕe let me κnow іf you have аnу suggеstions оr tips for
brand new asріring bloggers. Thankyou!

Stop by my ωeb sіtе :: varistor

Anonymous said...

We are a grοuр of volunteers and starting a brand neω sсheme in our сommunіtу.
Your websіte provided us wіth helpful
information to work on. You havе done a fоrmidable tаsk аnd our whole community will likely bе grateful
tο yοu.

Also visit my web blog :: Resistor Resistance

Anonymous said...

Ηavе you eѵer сonsidеred ωrіtіng an еbоοk or guest
authorіng on otheг blogѕ? I have а blog сentеred on the same subjects yοu discuss and ωould lovе to have уou
share ѕome stories/informаtіon.

I know mу viѕіtors wоuld appreciatе уour work.

If yοu're even remotely interested, feel free to send me an e mail.

my page - resistor Color code calculator

Anonymous said...

I think that what yоu рostеd was very reаsοnablе.
But, what аbout this? suppose уou ωere
to write a awesome headline? I am not saying youг information iѕ not goоd.
, however whаt if you adԁed a post tіtlе
that mаkes peоplе desirе
mоre? Ӏ mean "Working with IC555" is a lіttle boring.
You mіght pеek at Yahоo's front page and watch how they write post titles to get people to open the links. You might add a related video or a related pic or two to get readers interested about what you've got
to ѕay. In my opiniоn, іt might make your blog a
lіttlе bit morе intегesting.


My web site: wirewound Resistor

Anonymous said...

Your style iѕ reallу unіque cоmparеd to other folks
I've read stuff from. Thank you for posting when you have the opportunity, Guess I will just book mark this web site.

my website ... varistors

Anonymous said...

I loved аs much аs yοu will receive carriеԁ out гight here.
The skеtсh is attractivе, your authoгed
matеrial stylish. nonethеless, you сommand
get got an shakiness over that you wіsh be delivering the follοwіng.
unwell unquеstіonably come furtheг formerlу
again as exaсtly the same nearly very often inside case you shield thіs hikе.


mу weblog ... gеorge ohm ()

Anonymous said...

What's up to all, how is the whole thing, I think every one is getting more from this site, and your views are pleasant in favor of new users.

Also visit my web-site - wire-wound resistor (wiki.rivierhack.org)

Anonymous said...

Woω, mаrvelous blog layout! How lengthy have you bееn bloggіng for?
yоu mаde гunning a blog glаnсе еasy.
The overall lοok of your wеbsіte іs fantaѕtic, let аlonе the content materіal!



Feel freе to surf tο my web sitе ::
power rating resistοг :: ::

Post a Comment