# The 555 Projects

#### Wendy

Joined Mar 24, 2008
22,145
The 555 Projects

This thread is to allow easy access to these articles and what their status. If you have a good memory you will notice I scraped the previous text in this thread and am doing a total rewrite.

I’ve been working on The 555 Projects for a while, trying for slow and steady growth. I’m going to try to continue this, but I need to organize what I’ve done (and am planning on doing). I have quite a few projects still in my head, I’ll post them here to keep track of them.

A significant part of the work for any article is packing it. As I pack it I will tack to the stash points below this post.

I’ll continue writing my articles in the Feedback and Suggestions forum, though this could be moved to another area with no problem. If any of the moderators feel this needs done please feel free to do so.

My blog will be another route to these articles, basically this is for everyone to contribute and make suggestions. I have the links below.

The following table is to show the status of each article, where it is at, and future articles that may be written:

If anyone has an idea they would like to see followed up, please feel free to suggest it. There are no guarantees, but I’m always looking for something new that I feel will interest a beginner.

Because the forum software doesn’t do tables well, here are the links to the articles:

Wendyl's Index

The 555 Projects

Introduction to the 555
555 Schmitt Trigger
555 Monostable
555 Hysteretic Oscillator
555 Bistable Multivibrator
CMOS 555 Long Duration Minimum Parts LED Flasher
CMOS 555 Long Duration Red LED Flasher
CMOS 555 Long Duration Blue LED Flasher
CMOS 555 Long Duration LED Flyback Flasher
555 PWM Oscillator

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#### Wendy

Joined Mar 24, 2008
22,145
Stash point #1

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#### Wendy

Joined Mar 24, 2008
22,145
Stash point #2

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#### Wendy

Joined Mar 24, 2008
22,145
Stash point #3

#### Wendy

Joined Mar 24, 2008
22,145
Stash point #4

#### Wendy

Joined Mar 24, 2008
22,145
Stash point #5

#### Dcrunkilton

Joined Jul 31, 2004
422
Stash point #2
1. I have downloaded stash point #1 and stash point #2 files. And, it looks good.

2. I have added a new Chapter 8, " 555 Circuits" to the Experiments volume 6 and moved one of yourprevious submissions out of the digital ICs chapter into this new one. Your images have been renumbered as a continuation of the 45xxx.png series. This has been done to my local copy, not at ibiblio yet.

4. You have one photo submitted as a .PNG. We can actually handle .JPG for photos. In fact, we would prefer to have it in .JPG, since Tony has all of his photos in that format. I doubt that it will be any smaller as .JPG; thought, that would be a bonus. (Most all images are .EPS sources -- drawings and equations. The exception being photos and screen captures which are not. I find that your bit map drawings can be processed like photos-- from a source other than .EPS)

5. Since you are asking about progress, I should probably package the whole work in progress here, rather than working on it any more.

6. I unintentionally removed some <literal> CR </literal> tages from one of the early sections before I figured out that you intended to insert space. You will have to put that back in if I post the work in progress without reverting it.

7. The first section is the introduction. The second section is the "555 Schmitt trigger" moved from the digital IC chapter. The new sections follow. You will be able to see that the "555 Schmitt trigger" format is much different from your new sections which follow. The main difference is your use of subsections and subsubsections. As far as I know, the Schmitt trigger is the same format that Tony uses for the other experiemnts. We would prefer that format. You can also look at the .SML for some of his experiemnts.

I think that AAC does a little better without too many subsections and subsubsections. For example, I reworked the AC motors chapter so that it had more sections (which show on the left side menu) and fewer subsections and subsubsections. So now, AAC has a fully populated left side menu for the AC motors chapter instead of only two entries.

8. I will work an packaging the new chapter for attachment here-- soon.

9. I have uploaded 555.zip containing 555.sml EXP_8.html and renumbered images

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#### Wendy

Joined Mar 24, 2008
22,145
I may not understand subsections and sections as well as I might need to. I'll look at the first 555 Schmitt Trigger entry to see how I did it. I may post a PM asking questions later. I really do aims to please.

The picture as .png was an opps. My personal preferred format for simple B&W is .gif, I had a lot of conversions to do.

This will be my drop zone for future 555 articles. If you looked at the table you can see I have a lot of ideas on the subject, it will take a while to get them all done. I'll send PMs when I add new articles.

I really don't like <bigspace> as it is too much, so I'll be using the <literal> commands instead. Since you didn't mention it I assume it isn't a problem.

As always, Thank You.

*******************

I just reviewed my older edition of 555 Schmitt Trigger. I used <Sectiontitle> and <subsubsectiontitle> pretty much the same way. Are you referring to the <bigspace> vs <literal> format?

Is there a way to create a no pagebreak? The old Schmitt Trigger had a page break between the <subsubsectiontitle> and the paragraph in the .pdf file.

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#### Dcrunkilton

Joined Jul 31, 2004
422
I may not understand subsections and sections as well as I might need to. I'll look at the first 555 Schmitt Trigger entry to see how I did it. I may post a PM asking questions later. I really do aims to please.
You understand subsections and sections as well as I did back when I started writing chapters. They way you did it actually is good in the LaTex/PDF version.

The picture as .png was an opps. My personal preferred format for simple B&W is .gif, I had a lot of conversions to do.
you can replace the .PNG photo with the .JPG The image is 45034.png The replace ment should be 45034.jpg

This will be my drop zone for future 555 articles. If you looked at the table you can see I have a lot of ideas on the subject, it will take a while to get them all done. I'll send PMs when I add new articles.
They sound like good Ideas.

I really don't like <bigspace> as it is too much, so I'll be using the <literal> commands instead. Since you didn't mention it I assume it isn't a problem.
I suspect that the <bigspace> looks good in the LaTeX/PDF version, probably not so good in the HTML

I just reviewed my older edition of 555 Schmitt Trigger. I used <Sectiontitle> and <subsubsectiontitle> pretty much the same way. Are you referring to the <bigspace> vs <literal> format?
I would have to take a close look at the SML of one of the Experiments to see if Tony has used <bigspace> The Schmitt trigger was pulled from the SML which was used to publish it in the Digital IC chapter at ibiblio. And, I think it was up at AAC too. I suspect that I got the original file as a text file, and put the text between the tags that Tony used in one of his experiments. The format in 555 Schmitt trigger should be very close to what Tony had done for other Experiments. The only better reference would be to look at one of the existing chapters. I suspect that Tony used <bold></bold> tags instead of subsections and subsubsections.

Is there a way to create a no pagebreak? The old Schmitt Trigger had a page break between the <subsubsectiontitle> and the paragraph in the .pdf file.
I am guessing ( I don't know for sure) that the <pagebreak> appears in the Experiments chapter at the end of each experiment. In other words, this is a collection of lab worksheets which always begins on a new page. That way the individual labs can be disassembled into stand-alone handouts. This applies to the LaTeX/Pdf. I don't think the <pagebreak> has any effect on the HTML. It has to be put in the SML manually. I just repeat what Tony has done in the SML for other Labs.

#### Dcrunkilton

Joined Jul 31, 2004
422
The purpose of this post is to show the usage of sectiontitle, subsection, subsubsection in the Experiments chapter.

Here is a report on usage of sectiontitle in the SML of the Experiments volume. The number after the colon is the number of instances.
[dennis@localhost Exper]$grep -c "<sectiontitle>" *.sml 555.sml:9 about.sml:3 ac.sml:16 a_ic.sml:10 basic.sml:10 contrib.sml:2 dc.sml:18 d_ic.sml:9 discrete.sml:19 dsl.sml:9 intro.sml:3 This shows that "<subsectiontitle>" is seldom used in the SML files in Experiments [dennis@localhost Exper]$ grep -c "<subsectiontitle>" *.sml
555.sml:0
ac.sml:0
a_ic.sml:0
basic.sml:0
contrib.sml:6
dc.sml:0
d_ic.sml:0
discrete.sml:0
dsl.sml:0
intro.sml:3

This shows that "<subsubsectiontitle>" is not used in the other SML files of Experiments
[dennis@localhost Exper]\$ grep -c "<subsubsectiontitle>" *.sml
555.sml:44
ac.sml:0
a_ic.sml:0
basic.sml:0
contrib.sml:0
dc.sml:0
d_ic.sml:0
discrete.sml:0
dsl.sml:0
intro.sml:0

#### Wendy

Joined Mar 24, 2008
22,145
I can't reach the files you're referring to (I think). Can you attach one example of a .txt file for the experiments? Something you want me to follow?

#### Dcrunkilton

Joined Jul 31, 2004
422
The following is a 24 MB package of the whole Experiments source-- images and SML
http://www.openbookproject.net//electricCircuits/Exper/EXPsrc.tar.gz

The following is a 1 MB package including the SML and only the source images, not the derived images. For example most images are .EPS sources; the .PNGs which are derived with mogrify are not already included in the following. (Some images like photos are JPG or PNG source, the derived EPS are not included here.
http://www.openbookproject.net//electricCircuits/Exper/EXPtiny.tar.gz

These are the individual SML files at ibiblio. I can look at them with Firefox/Mozilla browser.

http://www.openbookproject.net//electricCircuits/Exper/ac.sml
http://www.openbookproject.net//electricCircuits/Exper/basic.sml
http://www.openbookproject.net//electricCircuits/Exper/dc.sml
http://www.openbookproject.net//electricCircuits/Exper/discrete.sml
http://www.openbookproject.net//electricCircuits/Exper/intro.sml
http://www.openbookproject.net//electricCircuits/Exper/a_ic.sml
http://www.openbookproject.net//electricCircuits/Exper/d_ic.sml

The d_ic.sml will have the Schmitt Trigger in it at ibiblio as I have only moved it in my local copy.

#### talking

Joined Dec 10, 2009
12
HTML clipboard In Bill Marsden's HTML clipboardCMOS 555 LONG DURATION text:

When the voltage across pins 2 and 6 reaches 2/3 of the power supply the flip flop is reset via internal comparator C1,

This should read: When the voltage on pin 6 reaches 2/3 of the power supply

When the voltage across pins 2 and 6 reaches 1/3 of the power supply the flip flop is set via internal comparator C2,

This should read: When the voltage on pin 2 reaches 1/3 of the power supply.

#### Wendy

Joined Mar 24, 2008
22,145

THEORY OF OPERATION

An observant reader will note that this is fundamentally the same circuit that was used in the 555 AUDIO OSCILLATOR experiment. Many designs use the same basic designs and concepts several different ways, this is such a case. A conventional 555 IC would work in this design if the power supply weren’t so low and a LED current limiting resistor is used. Other than the type of transistors used the block diagram shown in Figure 1 is basically the same as a conventional 555.

This particular oscillator depends on the pin 7 transistor, much like the 555 Monostable Multivibrator shown in an earlier experiment. The startup condition is with the capacitor discharged, the output high, and pin 7 transistor off. The capacitor starts charging as shown in Figure 2.

When the voltage across pins 2 and 6 reaches 2/3 of the power supply the flip flop is reset via internal comparator C1, which turns on the Pin 7 transistor, and starts the capacitor C1 discharging through R2 as shown in Figure 3. The current shown through R1 is incidental, and not important other than it drains the battery. This is why this resistor value is so large.

When the voltage across pins 2 and 6 reaches 1/3 of the power supply the flip flop is set via internal comparator C2, when turns off the pin 7 transistor, allowing the capacitor to start charging again through R1 and R2, as shown in Figure 2. This cycle repeats.
I see nothing wrong with the text, it is correct as is.