Introduction to 555 Timer: The Internal Block Diagram and the Pin Diagram Explained
ฝัง
- เผยแพร่เมื่อ 17 ก.ย. 2018
- In this video, the brief introduction to the 555 Timer IC has been given and the pin diagram (of 8 pin DIP 555 IC) and the internal block diagram of the 555 timer have been explained.
By watching this video you will learn the following topics:
0:20 Introduction and Application of 555 timer IC
0:50 Pin Diagram of 555 Timer IC
1:06 Internal Block Diagram of 555 Timer
1:48 Brief description of 8 Pins and basic working of the internal blocks of 555 timer
what is 555 Timer IC?
The 555 timer IC is a very popular timer IC and it is widely used in many timing related applications.
It can be used as an oscillator, LED Flasher, tone generator, Frequency division, and timing delay generation.
The 555 timer IC is available in many packages but most popular is 8 pin DIP (Dual Inline Package).
The following is the list of the individual pin of 555 timer IC.
1. Ground
2. Trigger
3. Output
4. Reset
5. Control
6. Threshold
7. Discharge
8. Vcc
In this video, the brief description of each pin is given.
If you see the internal block diagram of 555 timer IC then it consists of the following parts.
1. Voltage Divider Circuit
2. Comparator
3. SR Flip-Flop
4. Discharge Circuit
5. Output Driver Circuit
In this video, the function of each block is explained in detail.
By connecting the external resistors and capacitor to the different pin of this 555 timer IC, it can be configured as either Astable, Monostable or Bistable Multivibrator and can be used in wide range of timing related applications.
This video will be helpful to all the students of science and engineering in understanding the basic working of 555 timer IC.
#555Timer
#PinDiagram
#InternalBlockDiagram
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The timestamps for the different topics covered in the video:
0:20 Introduction and Application of 555 timer IC
0:50 Pin Diagram of 555 Timer IC
1:06 Internal Block Diagram of 555 Timer
1:48 Brief description of 8 Pins and basic working of the internal blocks of 555 timer
ok sir output block inverts the output.Awesome sir ,my bad .
Yeah MAN you got it right the OUTPUT block is actually a not gate..
10min video=10hr of reading about 555 timer...Very useful👌
These videos are like NCERT books. Every sentence is crucial and important to note. Otherwise, you will be lost. Loved it.
Great work.The concepts are explained in a lucid manner and provide in-depth conceptual clarity of the subject.Hats off buddy !!!!!
Can you also make such videos on microprocessor as it will be helpful for us.
Thank you so much, your explaination is clear and right to the point.
U explained in a clean manner thank u so much
Excellent. Much better than the book I was consulting.
Thanks, you are great teacher.
Helped a lot sir THANK U Very much
Love u brother u cleared most of my confusions of my electronics course keep it up ❤️
Thank you sir this video made 555 timer very easy to understand
As usual....great one..thanks sir
Thank you sir... Your videos are so helpful ... 💖
THANK YOU SO SO MUCH FOR HELPING TO STUDY FOR EXAMS !!!!
Wait it is for which exam
@@executorarktanis2323 diploma
@@executorarktanis2323 integrated circuits BTech
What exam
bro great work! your explanation is really fantastic.
Amazing teaching. Thank you so much. :D
better than VIT teachers lol
@@lemonspatula2545is vit means vit vellore
am i right bro
Great Job Brother 👌 you give us lot's of information which not give by our school/college. Excellent 👌🔥
Very good explain...
Thanks 😍
Excellent video sir,
it would be great if you could enlarge the size of the cursor as it is very difficult to identify different blocks while you explain them
literally the best explanation.
excellent explanation brother..!!!..thanks a lot...
Tqs for ur video I'm cleared of my doubt
sir tq somch I cleared my doubt
You are a God! You totally saved me!
अत्यंत प्रभावशाली।।। best video to explain 555 bro... Keep up the spirit high...
Yes you are right.....
sir, Can you say why we are using 555 timer ic instead of using opamp for astable & monostable multivibrators. Any specific advantage of using 555timer ic
Thank you so much for such a useful class....🎉
Great Sir, I am thankful
Clear explanation sir
Excelent .... No words to say
Superb explanation sir☺Tq
Superb explanation bro
Really great explanation 💔💔💔
Can I contact you with a question where I think I can use a couple of 555 timer circuits? I used to work with 555 timers many years ago but have forgotten a lot about them now. I have a one-off situation where I think two 555 timers will work for me but I don't want to go through the whole theoretical refresh process again. I just want a circuit I can build.
You can contact me on either facebook or Instagram.
The link is given in the descreption of the video.
EXCELLENT
Sir, you said that when the flip flop resets due to the high output from upper comparator, the output of timer is zero. But in diagram, the output is connected to Q'. So shouldn't the output be 1 at that time?
Okay sir, I got the reason. Isn't it because the output circuit is inverting? You said it later in the video 😅
Sir, the video is excellent. I loved it a lot from the signature tune all about electronics 😍
Wouldn't it just make sense to tie Q to the output rather than having to waste an inverter?
Same doubt I have
I did not understand how can Q' is high when the output us high
@@JayDubb410 i guess we are using an inverter usually a bjt amplifier circuit so that we are capable of driving a load
Sir plzzz do vedios on 555 timer as early as possible please sir😊😊
can you upload a video about 74193 counter IC
It's clear explanation.
If this 555 ic support only 15 volts, which ic need to be used for 230 volts energy in our real time scenario? Can you suggest?
The relay can be used at low frequencies with line voltage. And high voltage MOSFET switches are also available, which can be used at high voltages.
555 can be supplied with upto a max of 18V DC. You should use a rectifier to use it with AC....
I have a doubt on the voltage divider part
In the 1st node which is connected to the iverting terminal of the 1st opamp would be (Vcc/3) inspite of (2Vcc/3)
If you observe, at the inverting node, two resistors (R+R) are connected in series. So, the voltage at the inverting node would be (R+R)*V / (2R +R) = 2/3 Vcc.
Voltage drop across the resistor is only1/3vcc . So reduce vcc with 1/3vcc you will get 2/3 vcc is the voltage at the node
Sir.thank you
Awesome sir awesome 😊😊😊😊
sir you explained bjt as switch using capacitor is it just for explaining or capacitor is connected to it. I'm confused.
While designing the circuit using 555 timer, the capacitor is connected externally to 555 timer. And this discharge pin provides the discharge path through this transistor.
I recommend you to watch the other videos on 555 timer (Astable and Monostable Multivibrator using 555 timer) in which the external capacitor is connected to the 555 timer.
th-cam.com/video/iJYm_BGqa1A/w-d-xo.html
The transistor connected at Q bar of flip-flop should be PNP or NPN TRANSISTOR should be connected to Q of flip-flop
Thank you sir
I need to buy PWM for hydrogen production. Hydrogen unit need 220volt
2500watt. I have 220volt inverter. Which PWM should I selected
Plz tell me apnay yeh potential divider wala formula kesay derive kiya hy plz karkay bata dein yeh 2R kesay aya?
Hi,
I need a circuit that every trigger can discharge capacitor. So whenever a new trigger the timing will reset, and output willl only off if after delay time no trigger anymore.
Is it possible ? And how to achieve this
What do you do sir?
Working or Student?
How to generate difference number of pluses using ic 555 and ic 4017 ?
So sir we need to keep +Vsat and -Vsat of the two op amps as +1V and 0V respectively right
No, actually I was referring to the logic levels. Logic "1' And logic '0'. In 555 timer, the comparators are biased internally. We only need to apply the supply voltage to the Vcc pin.
@@ALLABOUTELECTRONICS ok sir ok sir
Thank you
@@ALLABOUTELECTRONICS oh sir so the Logic High is +Vsat and Logic LOW is -Vsat
So sir what are its typical/normal valies
Thank you
No, that is not right....
FM Demodulation with 555 possible?
sir the output of ic 555 is taken from Q bar instead of Q .
Thank you,sir
are u who i think you are
@@CooperStation01please elaborate
@@rahulanand3099 nah nevermind, thought I knew you
Sir what about Q bar in 3rd block
Sir
Is it true or a misnomer that the three voltage divider resistors are 5k Ohm thus the name 555 IC timer
Thank you
No, the name was chosen arbitrarily.
@@ALLABOUTELECTRONICS 👍
shouldn"t it be a sr latch rather than a flip flop as we are not using a clock signal here?? I might be wrong tho
Threshold voltage external we give voltage I want to know
I wish you create a similar video for op amp
Bro how the time was delayed by changing input voltages can u explain me
Please go through the monostable multivibrator using 555 timer video, you will get it.
Here is the link: th-cam.com/video/ypV6gdIJJU4/w-d-xo.html
How 2 voltage can be supplied at the same pin in threshold pin?? Please explain. Would not spark come out at this point??
Actually, there is only one supply to the threshold pin. I think what you understood is 1/3Vcc pin and trigger pin are connected right. But actually, they are not. (see, there is no small blue dot, which indicates the connection of two wires)
I hope it will clear your doubt.
@@ALLABOUTELECTRONICS ok thanks for replying.
Another......how value of control pin is made higher than the threshold pin while the 2/3Vcc remains connected to negative of comparator?? Does it mean when control is made higher, the 2/3Vcc remain disconnected?? Awaiting solutions again. Thanks.
@@tnamen1307 If you look at the internal digram, the 2/3Vcc is provided to the comparator using voltage divider right !!
And the control pin is directly connected to the inverting terminal of the comparator. Or just after the first resistor.
So, whatever voltage is applied at the control pin, the same voltage will appear as a reference for the comparator. Again here 2/3Vcc voltage is applied using a voltage divider, so KVL will not get violated even if we apply the control voltage to the same node. (As there is a resistor between the Vcc and control pin).
It would have been violated if the 2/3Vcc voltage is directly applied to the comparator from the supply (instead of using a voltage divider)
I hope it will clear your doubt.
@@ALLABOUTELECTRONICS okok very clear explanation. I need to recall my concepts on KVL!!! THANK. Sir!!!!
I want to build a ckt dat get triggered by sensor and high for 10 sec for indicator within dat time another push button get signal and after pressing push button another 45 sec the solenoid valve get activated.
How I can achieve this?
Pls help on this
You can use 555 timer as monostable multivibrator. The sensor output will act act as a trigger for monostable.
You can select the RC time constant to get 10s of time. Similarly you can also generate the trigger signal corresponding to push button and can give it to another monostable.
At the output of the monostable, you can connect the solenoid.
I hope it will help you.
Is my assumption that Q bar is high whenever Q and/or output pin is low, correct?
Yes, Q and Q bar will be always the opposite. And in 555 timer, the output of the Q bar is given to the output driver circuit, which is once again inverting circuit. So, the output will be opposite to Q bar.
Exactly.....
I have a question: at 7:07, the output is connected to Qbar, so i deem the output should be 1. Chould you please tell me where i am going wrong?
The Q bar is connected to the output driver circuit, which is the inverting circuit. That's why the output is 1.
I hope it will clear your doubt.
Oh ,yes. Thank you!@@ALLABOUTELECTRONICS
I too got this doubt... Thanks!!
Well explained
Does it matter with numberings
LM555 SOP-8 Timer IC and NE555N Timer IC between two of them what are the difference
LM 555 is a low power version. (CMOS version)
Nice video....keep on
What happen if we don't connect pin no. 4 to pin no. 8 when pin no. 4 is not in use . . . . . . ???
since the output is taken from Qbar ,why it is not opposit of Q.??
in video 6.58 and 7.51 time
Q bar is given to the output driver circuit, which is inverting driver.
That means if Q bar is 1 then the output of the output driver will be 1.
I hope it will clear your doubt.
@@ALLABOUTELECTRONICS thanks
Suggestion: use overlap symbol in your diagram else it's quite confusing.
How 2R is written in potential divider formula on 1st comparator
There are three resistors. And comparators are assumed to be ideal. So, using the voltage divider, the voltage across the node is found. See, the voltage at that node is the voltage across the two resistors. If the current flowing the resistors is I, then voltage at that node is I * 2R. And current I is Vcc / (R + R + R).
That means voltage at that node is 2R* Vcc / 3R = 2/3 Vcc. I hope, it will clear your doubt.
Please explain about Hamming code generator
sir i can become an engineer just bu listen to this video
Good my doubt is gone 👍
9:34 how did you take Q' as 1 when your are saying output is zero at that moment
Because the output block shown in the diagram is the inverting buffer.
@@ALLABOUTELECTRONICS i got it thanks man
The diagram is incorrect sir. The output buffer is connected to Q, not Q' as shown in the video.
Please correct it.
bro if u connect to q u will hv to use inverter so meaning is same
@@ytstudy7007 please see 9:17 - 9:25 🙂
The output circuit is basically an inverter circuit. So since Q' is connected to the output, it will get inverted and we will ultimately get Q at pin no. 3
time period expression for the output wave?
Please check the entire playlist on oscillator and Multivibrator. I have made seperate videos on how to design a Monostable, astable Multivibrator using 555 timers with equations.
@6:15
U mean
Trigger vlg=to Vcc vlg
Now Vcc vlg is which vlg (supply vlg (pin no 8) or reference (1/3Vcc) vlg )
Voltage at Pin 8
Can upload designing of multivibrator
I have already uploaded a few videos on how to design astable and monostable multivibrator using the op-amp.
Very soon I am going to upload more videos on the design of these multivibrators using 555 timers.
Sire its a year now........ You're yet to
at time 7.45 to 7.50 you say output of flip flop =0 (Q=0,Q'=1),because of this output of 555 timer is also =0 but the output of 555 timer connect to Q'.i did not understand here.
actually here the output stage is inverter. That is why Q' is connected to the output state. But I should have mentioned that explicitly. I hope, it will clear your doubt.
@@ALLABOUTELECTRONICS Thank you so much
without clock how does flip flop works there sir
please clarify my doubt sir, I have a presentation tomorrow
Technically, here it is a SR latch. But in general there are called Flip-Flop. ( Both latch and Flip-Flop). And that's why you must have heard some people are using the word, clocked flip- flop. But I hope, you got the point. If you still have any doubt then let me know here. Good luck for presentation 👍🏻
@@ALLABOUTELECTRONICS I have got your point
Thank you for replying
i still cant understand why this ic called timer?
Top 10 unsolved mysteries of all time
I think maybe you'll find the answer in the astable and monostable multivibrator videos.
You can change the output after a predefined time ....
Why to discharge the capacitors when the output is in low state?!
Capacitor is connected in such a way that it discharges when Q=0
When reset pin goes high then the output should be zero sir ?
please explain this to me sir and aslo the discharging part
@@neerajhebbar7313 When Reset pin is low then the output of the 555 timer will become zero (Because it is Reset -bar ). So, whenever it is zero, it functions and makes the output of the 555 timer zero.
For the discharge pin please check the video on astable and multivibrator using 555 timer. I have explained there in detail.
Here is the link:
th-cam.com/video/iJYm_BGqa1A/w-d-xo.html
And after that, if you have any doubt then do let me know here.
@@ALLABOUTELECTRONICS Thank you so much sir i am your student from 2 years and your teaching skill are great i wish i could get a sir like you next sem and sir thanxx for the quick response
@@ALLABOUTELECTRONICS So is it compliment of reset right so it makes out put of the 555 timer ic to zero if m ryt jst give it a like sir and thank you once again
also please explain about 555 timer as Schmitt trigger , astable and monostable multivibrators... thank you
Yes, definitely I am going to make videos on it soon.
Output is NOT(inverse) of Q or Q' ??
In SR flip flop isn't S connected to Q and not Q'?
Are you referring to the block diagram of SR flip-flop shown in the internal block diagram?
@@ALLABOUTELECTRONICS yes
@ursula das
No. R is always connected to Q. But when we make the diagram of flip flop using 2 nand gate, internally, S' is connected to Q and R' is connected to Q', and when we implement the circuit using 4 nand gates in which S' and R' are changed to S and R with a not gate in the front, which results in S connected to Q and R connected to Q'. Try drawing a diagram with the explanation given. You may understand.
It's a block diagram so connection from input to out are not shown. But he gave us the truth table and that is how it works. When s=1 r=0 Q is high, Q not is low and visa versa.
While explaining the flip flop circuit you have considered the output as general circuit but when you are explaining discharge circuit you said it's an inverting circuit
What should we consider
ty
Suprrr
Good
👏
What is mean by ttl ??
Transistor transistor logic
please explain the function of pin 4,5 and 7....its not clear
Pin no- 4: Reset pin is for simply to reset the output.
Pin no - 5: Control pin is used when you want to provide some other reference voltage to two comparators. (Generally, the reference voltage is 2/3Vcc and 1/3Vcc)
Pin no-7: Discharge pin is used to discharge the external capacitor.
For more info about the pins, please check the video on astable and monostable multivibrator using 555 timer.
Where in detail I have discussed the use of these pins.
Here is the link:
Astable Multivibrator using 555 timer
th-cam.com/video/iJYm_BGqa1A/w-d-xo.html
Monostable Multivibrator using 555 Timer
th-cam.com/video/ypV6gdIJJU4/w-d-xo.html
@@ALLABOUTELECTRONICS thank you sir...grt work
Three together means something as named it.
Sir u can make this video in 15 or 16 minutes so that we can understand it easily
You can go through my videos....
Block diagram acche se dikayi nahi de rahi.. scrn par typing ki wajah se....
How can it be when Q is 1, Q’ is also 1 ? Q’ isn’t Q(t+1) sir.
No, Q' will be zero. But the output driving circuit is inverting circuit. So, the output of the timer will be 1. I think I should have specified that the output driving circuit is inverting driver circuit.
Anyway, I hope it will clear your doubt.
I see many tutorial, Web even book to learn 555 Timer IC, All of them frustrated me,
Now I got the clear picture, (Thanks dude)
I more question what about comparator's - and + sign means ?
Hope you will replay to me.
The comparator has two terminals. Inverting (-) and non-inverting (+).
When the voltage at the + terminal is more than - terminal, then output of the comparator will be high. Similarly, when the voltage at the negative terminal is more than + terminal, the output will be low.
For more info, you can check my video on comparator.
Here is the link: th-cam.com/video/k9zQjEaKtfk/w-d-xo.html
Here , when Q is zero u r saying output is zero but output is connected with Q bar so output should be 1.
There is a bubble at the output side, so the output is getting inverted after that. ( I should have specified that in the video though ). That's why Q' is applied. I hope, it will clear your doubt.
@@ALLABOUTELECTRONICS ok , thank u for clearing doubt .