I understand OHM's Law, and have a conceptual grasp of RCL circuits, but am a little weak on the math. I am good at math, even a little calculus, just weak on RCL math.

I am trying to understand the 555 timer. I have seen various 'cookbooks', but it's like someone is trying to teach me about internal combustion engines, when I don't understand campfires.

The monostable multivibrator is generally presented first, but it does not utilize each pin individually, as some are tied together. I am trying to get a snapshot of all features offered by the 555.

I have figured out that, if I have a push button providing the trigger signal, I would want to have a capacitor in series, to limit the pulse width. Regarding the value of the capacitor, I suppose I could use trial and error.

I have a breadboard and some components on order. I'm just trying to read up a little bit in the meantime.


closed as primarily opinion-based by Scott Seidman, Matt Young, PeterJ, Daniel Grillo, Asmyldof Feb 19 '16 at 17:13

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ Have you read the 555 datasheet? What specifically don't you understand about it? \$\endgroup\$ – Dave Tweed Feb 19 '16 at 12:23
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    \$\begingroup\$ If you Google "555 tutorial" you'll find just exactly what you're looking for, thousands of times over. \$\endgroup\$ – EM Fields Feb 19 '16 at 12:30
  • \$\begingroup\$ Like this or this video series. \$\endgroup\$ – rdtsc Feb 19 '16 at 12:36
  • \$\begingroup\$ This falls into the category of "what textbook should I read?"-type questions for me. \$\endgroup\$ – Scott Seidman Feb 19 '16 at 13:28
  • \$\begingroup\$ You may also find this of interest: evilmadscientist.com/2014/555v2 (a 555 made from discretes). \$\endgroup\$ – Chris H Feb 19 '16 at 16:40

To get a better overview of all the features of an IC, you're usually going to want to read the product datasheet, rather than expecting any example circuit to demonstrate all of its capabilities.

If/when the datasheet gets a bit too deep for you, it may help (when using as popular a component as the 555) to read The Wikipedia Article for an easier-to-understand overview.

Finally, if you still want/need some (more) example circuits to follow, or want more information/calculators/etc for using the chip, you could always read the Entire Website Dedicated to 555 Timers.

  • \$\begingroup\$ Excellent website; definitely a keeper! :) \$\endgroup\$ – EM Fields Feb 19 '16 at 13:07

Study resistors, transistors, voltage comparators, voltage dividers, R-S latches(flip-flops), and this data sheet.

There's an error or two in its graphics, and if you can find it/them you'll be well on your way to understanding the 555. ;)

You might also want to go to the source and study Hans Kamenzind's book, free, from:


Click on "Download Book" at the end of the third paragraph.


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