Just made a 555 timer beginners tutorial for anyone starting out - Page 1
Forum section: electronics / beginners

author: skinny
author_rank: Contributor
timestamp: August 17, 2015, 02:07:48 am
content: 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!

author: rs20
author_rank: Super Contributor
timestamp: August 17, 2015, 05:39:32 am
content: 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, itremembersormaintainsthe 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!

author: skinny
author_rank: Contributor
timestamp: August 17, 2015, 11:13:53 am
content: 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!

author: drws
author_rank: Unknown
timestamp: August 17, 2015, 06:35:29 pm
content: 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.

author: rs20
author_rank: Super Contributor
timestamp: August 17, 2015, 10:30:21 pm
content: Quote from: skinny on August 17, 2015, 11:13:53 amHmm, 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.pdfhttp://www.ti.com/lit/ds/symlink/ne555.pdfhttps://www.fairchildsemi.com/datasheets/LM/LM555.pdfhttp://www.diodes.com/datasheets/NE555_SA555_NA555.pdfhttp://www.intersil.com/content/dam/Intersil/documents/icm7/icm7555-56.pdf

author: skinny
author_rank: Contributor
timestamp: August 20, 2015, 11:55:51 pm
content: 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.pdfI cut out the diagram on page 3.