Jason, I've read just about every book from our public library on trying to understand the basic building block of IC's: the 555. I have also watched most of the 555 videos here on youtube, so I feel that I am fully qualified to say that you have the easiest to understand and most comprehensive, in-depth, excellently articulated explanation on the 555. Well done! Thank you for spending so much of your valuable time on creating Part I and Part II and also the Math Behind the 555. Bravo!!

Thank you! Except for the fact that you never said what 'e' was this was the best video tutorial I have seen. Clear, simple, sped up past the laborious parts, no crappy music etc. I appreciate the time you spent making/editing it too!

I love your videos. The detailed information you provide and the format in which you provide is exceptional!

More maths stuff Please, buck, boost, op amps, inductors, circuits, mosfets ......... . I hope i can apply this to other areas and make it work. keep up the good work, very clear.

In engineering, they teach that if you wait five time constants (5RC) the capacitor is charged "all the way" or "it's safe now", etc. Something like you are saying at about timestamp 7:00 I work with high-energy electronics, and had to learn for myself that this cam be an assumption that will KILL YOU!! I realize that this will not be usually encountered in 555 circuits, but be sure you are aware of this on large scales, such as the big "pulse" and "energy" caps. If you wait 5RC, then the cap is discharged down to 1-exp(-t/RC) or 1-e^(-5), which is over 99% discharged. Now consider the huge capacitors that so many people are using for such things as "wire exploding", "rail guns", "can-crushing", etc. I have seen some cap banks that are charged to energy levels like 75kJ. If such a bank is discharged 99.3% (5RC) it is left with an instantly lethal 525 Joules!! I believe that these things are the most dangerous electrical components! BTW: at about timestamp 4:00 I think there is a mistake in the datasheet in the last formula visible...isn't the duty cycle given by "D=(Ra+Rb)/(Ra+2Rb)" THANKS MUCH FOR THE VIDEO!

No words to say how awesome you explained…., great work. Keep it up bro

You've produced a great series of videos explaining the 555 Timer, thanks. I realize it's been two years since you posted, but the videos are "timeless". You really have explained slowly, and with some great grocery bag illustrations (from Whole Paycheck), what the 555 does, how it works, and how to determine what (and size of) components needed. The one thing that slipped me up on the final calculation of R sub b resistor was the 820 picofarad capacitor. In my HP 12C (the best calculator every made!), I converted 820 pico farad to micro farads (1/1,000,000). I believe you may have done so in your TI equation, but was just difficult to see that. Or, maybe you converted to milli farads AND converted the frequency to Hz, I couldn't tell.

Skinny R&D Thank you for this video. I have a much better understanding of how a 555 timer works now. Also learned the formulas for calculating the time to charge a capacitor.

Hi... Just came across your KZfaq videos... I really like your brown paper bag "Board" for displaying your information. I've viewed a couple of your older vid's and find them very informative as I am a bit Neophyte to electronics. I hope I will not become to much of a pest as I know I will be asking questions down the road :-D Thanks again for your informative and instruction videos... Keep up the great work.Sal.

you should add a link at 11:14 to a separate video working out the equation long hand.

Thank you so much!!! This helped a bunch.

I love your videos. I also initially used a 555 for a 40kHz Ultrasonic Transmitter. Although the 555 did the job admirably (after coming up with many non-standard resistor values until I got "close enough"). I eventually replaced the circuit with a 3.2mHz oscillator can through a toggling flip flop to get 1.6mHz and then divided that down to 40kHz. It didn't really perform much better than the 555 version, except for stability. :) I am subscribing.

Thank you. I'm surprised I understand the part of the video explaining the constants 0.693 and .05 is because of the 3V and 6 V concept. I'm really weak with algebraic manipulation. I have to use examples (like you showed) and then write simple spreadsheets to do my math.

Really good explain!! Thank You

Great videos on the 555! I'm a beginner when it comes to electronics, so these really helped me understand the logic behind how these work. There is a project that I've been messing around with where I have a signal pulse coming from an electric motor which pulses twice per rotation, so the frequency is variable and equal to two times the RPM of the motor. What I would like to do is use this signal to generate another pulse which is equal to three times the RPM of the motor. Do you think that there might be a simple way of accomplishing this (electronically), aside from using something like a microchip to be able to interpret the original pulse signal and calculate what the signal would be if multiplied by 1.5? Ideally, I would like to have every second pulse of the original signal synced to every third pulse of the generated signal. Edit: I may just end up creating a custom rotor with 3 magnets and a hall-effect sensor to get the specific pulse signal that I want instead of using the signal coming off the existing wire. I'd prefer not to add additional mass to the rotating component of the motor, but it's the easiest thing that I can think of for testing purposes.

Thank you so much!

Awesome video Keep working good We are with you

Skinny R&D! Thank you for sharing your experience. I have a unrelated question for the topic, and that is what is the best device to emit ultrasonic frequency in air? As I noticed Speakers are too slow to vibrate for the ultrasonic frequency range.

Thank you

Would you please explain in brief about pin 5 of the ne555 timer ic.

The circuit and its math becomes easier if you control the astable multivibrator by a single resistor between the output pin 3 and the timing capacitor pin 6, leaving the discharge pin 7 unsused. In this way you also achieve 50% duty cycle.

Hi Jason. How can I control the duty cycle of the 555 timer in astable mode from max value, down to about 40 or 50% using LDR without significant change of the frequency? My goal is to control the brightness of big LED clock depending on the ambient light. So in the daylight it should be on full brightness and during night the brightness should be down to 40 or 50 %. My LDR values: light resistance about 1.4K, dark resistance is about 20K. By the way, subscribed and hit the bell as well.

Nice explanation and nice video. However, I think it's a bit of a belabored explanation. The 0.693 comes from the fact that the voltages swings from 3V to 6V for Vs = 9V, i.e. exactly a factor of 0.5 between 3V and 6V. This factor of 0.5 is constant regardless of Vs because the voltage swing is from 1/3 to 2/3 (i.e. exactly a factor of 0.5 = (1/3) / (2/3) ).

Thank you 😊 for explaining every content. ..

hi, how to calculate 555 timer blinking rate that just using one resistor Rb only?

what Happens if you change the 10nF cappacitor (between pin 5 and ground) to a different value? is there a formula?

Thank you very much for these educating videos!!

Great video, but what about the duty cycle? How do i make a 50% duty cycle oscilator

I've been watching and enjoying your 555 timer videos. Hope you're still checking the comments. I didn't see you address, or any comments about, making the output low time 3 times longer than the output high. Is this possible with a 555 timer or cascading 555 timers? For instance, say I want an LED to blink for .5s then turn off for 1.5s. The cascade example used Vhigh=Vlow. I tried running the numbers with Vhigh=3Vlow, but I ended up with negative values when I combined the equations from the datasheet.

Thank you so much for the video!

Sir! Im Confused on the calculation. (1-e .693RC/RC) = (.0499926) How???

Where did you get that 1/5 for capacitor charging?

yeah! great video as usual..... please cover all types of multi vibrator. please make that happen soon . thanks for helping !

Oh another question, what is the value of the cap to ground from pin 5?

awesome videos man.. keep em coming

ultra sonic what? xD what's that thing you builded?? and can you explain more the frequency? lets say i want an led to ligth up for a secand and then be of for a secand does that makes my F=0.5hz?? (F=1/(1+1))

You got an excellent channel. Though I'm very bad with the math... How would I work out a 2hz freq for a bike flicker light? I roughly guessed out the math for 2hz using (1kohm+2x1kohm) x 0.000220 farad or 220uf cap but it was all guessing took hours lol.

Thank you so much we wanaa more tutorial

Ps .......... great work .......... of course , the other question is , how accurate is the 9V , as i ' m sure that has a coach & horse of " exactly " , running through it ' s garden . And in reality , is this not the problem ? We a sold a digital pup on the horns of an analogue dilemma .......... Ok , this may be a better solution of an analogue only dilemma .......... but it ' s still a dilemma .

i wanaa explain shift register can you please

why did you use formula instead of numbers its very confusing but whatever

0 . 39 "..........hit 40 KHz exactly ............. " how exactly ? +/- 0.5 % ? +/- 5 % ? ............. how exactly is exactly . A gold band or a silver ?

What happens if you short R(a)?

great video! (: