Talk:555 timer IC

Being a potentiometer has little to do with being a low resistance.

I noticed the following edit that added:

> "This is the reason why R1 shouldn't be a very low resistance, such as when a variable trimmer or potentiometer is used instead of a fixed value resistor."

But being a potentiometer doesn't really have much to do with being a small value. I have a box of potentiometers of all sizes, up to 10 MEGAohms. I guess if you have the wiper almost at one end then the resistance could be small, but still that is not worth mentioning. I would just leave the sentence at "This is the reason why R1 shouldn't be a very low resistance." with a period. Em3rgent0rdr (talk) 21:02, 22 January 2025 (UTC)

It's a real problem for newbies. I've seen plenty of 555 timer schematics across the internet that incorrectly substitue a trimmer or pot for R1. Obviously the correct way to do it is add a series resistor to the trimmmer / pot, but that's not what they do. Maybe change to "R1 should not be replaced with a trimmer or potentiometer unless a series resistor is added" or some other variation that makes it more obvious. It it was really obvious, then we wouldn't see incorrect schematics on the internet. • Sbmeirow • Talk • 22:20, 22 January 2025 (UTC)

ok. So I would write the bullet like:

"Because the internal discharge transistor shorts the DISCHARGE pin to GND when draining the capacitor, R1 should be large enough to keep the DISCHARGE pin's current below the maximum current rating of the internal discharge transistor. Therefore, a variable trimmer or potentiometer should only be used if it is in series with a fixed value resistor to ensure R1 will always be large enough."

It might also help to give an equation for R1_min. Em3rgent0rdr (talk) 03:32, 23 January 2025 (UTC)

I quickly found the following failures from an internet search. • Sbmeirow • Talk • 22:42, 22 January 2025 (UTC)

Wikipedia article is not a how to guide. Absolutely none of these "correct way" "incorrect way" based on one's own experience should be introduced into the article space. It must be backed up with reliable sources. The various sources mentioned below are not good sources anyways. Graywalls (talk) 08:02, 11 November 2025 (UTC)

Wikipedia:You don't need to cite that the sky is blue • Sbmeirow • Talk • 18:03, 11 November 2025 (UTC)

@Sbmeirow:, I'm ok with leaving calculations but warning/advise about how it should or should not be done when certain configurations are used seems to unnecessary. Graywalls (talk) 21:40, 11 November 2025 (UTC)

1A) https://www.instructables.com/Build-an-Atari-Punk-circuit-on-a-breadboard/

1B) https://makezine.com/article/craft/music/collins-lab-atari-punk-console/

1C) https://samvssound.com/projects/synthesizers/atari-punk-console/

2A) https://www.circuits-diy.com/adjustable-timer-circuit-using-555/

2B) https://www.elektropage.com/default.asp?tid=24

2C) https://free-circuitdiagrams.blogspot.com/2011/05/timer-555-schematic.html

Original research concerns

As I check claims against sources, I am finding claims made that are cited, but fail to verify in accompany sources and some that are not cited at all. I suspect the article possibly contains reflections based on personal experience and reflection by some Wikipedia editors. Graywalls (talk) 18:11, 11 November 2025 (UTC)

Yup, a common problem here. Editor A adds a clear and well-sourced statement to an article. Editor B arrives a year later, and wants to "fix" what's written - instead, writes something different from what the source says. The entry reads plausibly, so nobody actually checks it against the source. A serious flaw of an "encylopedia that anyone can edit". cheers. anastrophe, an editor he is. 18:44, 11 November 2025 (UTC)

Theres inherent and not easily repairable problem with wiki: anything printed on paper is instantly considered trustworthy "source". For this article - it chronically includes exaggerated claims like "most popular chip", "billion of pieces yearly" and such. And references that to old and silly hobbyist books. Well, it was and partially still is popular with hobbyists (which makes out miniscule market), but is not really needed in industry anymore. Switchmode power supplies got their own specialized chips, and generic beepy blinky things are designed with microcontrollers. There are no sensible uses of 555 in industry anymore. Thus, those claims about "most popular" and "billion" seem to be highly doubtful. ~2026-35273-70 (talk) 12:23, 17 June 2026 (UTC)

Bad readability of gallery pictures in dark mode

The pictures in the "Internal schematic" and "Pinout" sections are hard to read in dark mode due to black lines on dark background. Sadly I lack the skills to adjust the galleries to display a white bg for the pictures.