### Author Topic: Just made a 555 timer beginners tutorial for anyone starting out  (Read 2739 times)

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#### skinny

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##### Just made a 555 timer beginners tutorial for anyone starting out
« on: August 17, 2015, 02:07:48 am »
Hi Guys,

I tend to learn best when I have to teach it to someone else, so this weekend I put together a 555 timer tutorial. I finally understand some of what is going on internally and I hope what I put together might help others like myself.

If you have any comments about anything said, I'd love to hear them because I always want to learn.

Thanks!

#### rs20

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##### Re: Just made a 555 timer beginners tutorial for anyone starting out
« Reply #1 on: August 17, 2015, 05:39:32 am »
Nice video! I'm not the best person to ask because I already know 555s well, but just a few suggestions:
-- You didn't really explain the key property of a flip flop, which is that when R=0 & S=0, it remembers or maintains the previous state. This is pretty essential as it defines the difference between a 555 where the cap voltage is 1/2Vcc on the way up, vs 1/2Vcc on the way down. I think you ought to mention one of those "stateful" type keywords, or else you're making it sound like it's just some sort of weird logic gate that just outputs whatever S is.
-- Random note, you need a fullscreen HD to view the video, people on phones might have a hard time to make out the little diagram in the middle.
-- Also, this is much more a matter of opinion, but I think it's not a great idea to use plain boxes for comparators and flip flops. You don't even have the different inputs and outputs labelled, and if your viewers ever go to a real 555 datasheet, they won't recognise anything. I can see the counterargument that words are easier to recognize than shapes, but I'm not convinced. Also a matter of opinion: using a block diagram where the pins are "in the right place" is ill-advised, as the block diagram looks like spaghetti and doesn't flow from left to right like a nice schematic does. The counterargument that it's "easier" to map to a real chip is questionable in my mind, and also not exploited by your presentation in any case.

But I'm nitpicking!

#### skinny

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##### Re: Just made a 555 timer beginners tutorial for anyone starting out
« Reply #2 on: August 17, 2015, 11:13:53 am »
Thanks for the feedback. I completely left out the R=0 and S=0 state and I didn't think much about people using a phone to view the video. The printed schematic I was working from was cut out of the 555 datasheet, so it shouldn't have taken away anyone's ability to read the datasheet. You are correct though that I didn't label each pin according to what it's actually called. Thanks for perspective. It will definitely help me out with the next video. Have a great day!

#### drws

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##### Re: Just made a 555 timer beginners tutorial for anyone starting out
« Reply #3 on: August 17, 2015, 06:35:29 pm »
Nice video. I'm only an amature at this and found it useful. I've watched many other videos on the 555 and this was simple and easy to understand.
I'd agree with a point made earlier, on an iPad it was a bit tricky to read/see some details in your diagram without moving the iPad up close. (Old eyes also played a part there).
I've subscribed, hope to see more.

Also watched your network tap video, initially thinking "a passive network tap for gigabit copper?" and then saw your pin 7/8 'cheat' to get back to 10/100mb. Nice idea.

#### rs20

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##### Re: Just made a 555 timer beginners tutorial for anyone starting out
« Reply #4 on: August 17, 2015, 10:30:21 pm »
The printed schematic I was working from was cut out of the 555 datasheet, so it shouldn't have taken away anyone's ability to read the datasheet.

Hmm, where are you getting "the" datasheet from? Some hobbyist-focussed site? Because it's clearly not one of the first 5 555 manufacturers on digikey  :
http://www.micrel.com/_PDF/mic1555.pdf
https://www.fairchildsemi.com/datasheets/LM/LM555.pdf
http://www.diodes.com/datasheets/NE555_SA555_NA555.pdf
http://www.intersil.com/content/dam/Intersil/documents/icm7/icm7555-56.pdf

#### skinny

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##### Re: Just made a 555 timer beginners tutorial for anyone starting out
« Reply #5 on: August 20, 2015, 11:55:51 pm »
Thanks drws. I'm glad you found the videos helpful. Also, thanks for the subscribe. I'm going to try and post another one this weekend.

rs20: The datasheet I used is from Texas Instruments: http://www.ti.com/lit/ds/symlink/lm555.pdf

I cut out the diagram on page 3.
« Last Edit: August 20, 2015, 11:57:38 pm by skinny »

Smf