Discrete 555 timer kit

misterT

Well-Known Member
Not sure if this fits any other sub-forum so I post it here. Long video, but good waste of time.

jpanhalt

Well-Known Member
The question had to do with the flip-flop and what happens to the inverted output. That drives the discharge transistor, which has been the subject of some discussion in the past on ETO. Anyway, I found this diagram on an educational site (but lost the actual URL), which I think is a pretty good drawing:

John

large_ghostman

Well-Known Member
I like the video. How about putting it in the video section? Then it wont get lost in here in a few weeks It never occurred to me that you could make a 555 from transistors, i might have a go at doing this over xmas.

jpanhalt

Well-Known Member
It never occurred to me that you could make a 555 from transistors, i might have a go at doing this over xmas.
Oh, how far we have come. There are a lot of us here who remember early IC's being advertised with the equivalent number of transistors. Moore's law added some formality to that (http://en.wikipedia.org/wiki/Transistor_count ).

John

large_ghostman

Well-Known Member
Now i think about it is pretty obvious . I must start to switch on my brain, before touching the keyboard!

cowboybob

Well-Known Member
It is fairly remarkable (from an analog-phile's point of view ) what functions a 555 can be configured to perform. From my experience:

1. Self triggered One shot mono-stable (ms)
2. Triggered ms
3. Self triggered a-stable (as)
4. Triggered as
5. Self triggered flip-flop (ff) (selectable On or Off initial state of output depending on use of the Reset and Trigger pins)
6. Triggered ff (as above)
7. Single or dual triggered ff (in SIM single trigger worked, but in real life never could get it to work )
8. Cascade two of them for dalayed timer (also self or ext. trigger) Cannot cascade three or more.
9. When used in conjunction with a CV pin bias: Comparator, e.g., level sensor, hysterisis control, etc..

5. & 6. make a very handy Solid State latch, e.g., as a bounceless, low power Vcc supply (for small mechanical relays, other 555 circuits, etc.).

3. & 4. are configurable for both frequency and pulse width.

Did discover that in SIM for an ff circuit, the use of the Reset pin (as a trigger) was simply a bias issue, but in real life I needed to add a cap to ground (from the Reset pin) for output state stability.

Additional combos of all of the above.

No doubt more uses that I haven't made use of thus far...

ghostman11

Well-Known Member
I would love to see one done with VALVES! Now that would be a kit

cowboybob

Well-Known Member
I would love to see one done with VALVES! Now that would be a kit
Bunch of triodes and you're there!

Oh, how I miss HeathKit . (Which I could never afford - had to go with Knight Kit...)

ghostman11

Well-Known Member
I have heard of Heath Kit, Apparently everything in kit form up to a space shuttle

jpanhalt

Well-Known Member
Oh, how I miss HeathKit . (Which I could never afford - had to go with Knight Kit...)
Similar experience here. Everything I built was Knight Kit. The last one I built was the oscilloscope.

John

cowboybob

Well-Known Member
Similar experience here. Everything I built was Knight Kit. The last one I built was the oscilloscope.

John
Back in 1958 got the "Span Master' kit for Christmas, then in 59' bought the T-50 xmitter and the R-100 rcvr kits (my first novice Ham set,  from a paper route). Got all my parts from Allied Radio in Chicago. Still remember the smell of the components when I opened the box (not really different from today with a box of goodies from Digikey!).

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jpanhalt

Well-Known Member
@KISS
I cannot get the first link to work. The second is an animation, and they generally turn me off, but it has been swiped by many others including the third. I wish I could find the original source for the animation. It looks like something Tony van Roon would have done, but apparently that is not the case (http://www.sentex.ca/~mec1995/gadgets/555/555.html ).

The first place I go for 555 information is AN170 from Philips, which for some strange reason is no longer available. I uploaded it to ETO awhile back: http://www.electro-tech-online.com/attachments/555an-pdf.52952/

John

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KeepItSimpleStupid

Well-Known Member
I couldn't get it to work either, so I removed it. I should have checked the returned links.

glossywhite

Member
Here: http://shop.emscdn.com/catalog/emskits/555/kit/555_datasheet_RevA3.pdf
Now members won't have to listen to him.

Ironically, I made almost the same comment as you make on another forum. Looks like a fun waste of time.

John

I like Dave; he's a lovely guy when you get used to him, and he puts A LOT of hard work and detail into his videos; detail that most people overlook, forget or just cannot be bothered with. I admit, however, watching this kit being built *in realtime* was one of the most tedious things I've ever suffered... but I love 99.999% of his videos; he's a good bloke, a nice one.

Miervaldis

New Member
Awesome video! I love it And yes, it was interesting even after an hour