Alt-BEAM Archive
Message #09629
To: "beam@sgiblab.sgi.com" beam@sgiblab.sgi.com
From: Brad Guillot mach50@netzero.com
Date: Sun, 30 Jan 2000 12:14:54 -0600
Subject: [alt-beam] Vairable Threshold SE question
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I've had some problems solarizing the PSH circuit, and have tried
several solar engine designs to solve this problem. The 1381 se that
Darell Johnson uses is something i am not familiar with (an adaptation
of the suneater?) and i cant get it to trigger in solar power even
though it seems to work fine on batteries. So next i tried a PM1 type se
found at beam online. This solar engine seemed to have problems turning
off so i ruled using it out. I know a plain old 1381 shouldn't work
because the load has to be a motor or a coil. I believe this is because
the cap has to be completely drained to turn off the transistors???
This all leads me to my question: Will the below circuit work to drive
the Power Smart Head circuit? Does it require that the main cap be
completely drained to turn off like the traditional 1381? I ask this
because Wilf said that it was similar in operation to the clroplast and
i know that the clroplast turns off long before the main cap is drained
making it a more efficient se that the 1381. I would just buy parts for
a clroplast, but I'm very broke right now so I was trying to find
another way. I really want to finish this project after it has been
shelved so long and this is the last snag i think i will need to
overcome.
Any help would be appreciated very much,
thanks
Brad
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9630 Sun, 30 Jan 2000 13:30:57 EST [alt-beam] Re: Bicore question beam@sgiblab.sgi.com Meabadboy@aol.com In a message dated 1/30/2000 12:29:23 PM Eastern Standard Time,
phillip@ryals.com writes:
<< All I'm left with now, is perhaps that I ruined the chip with heat. >>
I might ask this ~ did you soder directly to the terminals of the 74 chip??
If you did then you made your first mistake ~ I have burnt up a lot of chips
this way myself ~ most chips cannot take this heat of free forming like is
shown in the webpages of other peoples bots. ~ with practice and a little bit
of time ~ and with very low heat soder iron ~ heat sink clips, etc. ~ you
will be able to get this done with out damaging the chip ~ but........... I
have a better suggestion for you:
Take a simple IC socket that you would soder to a circuit bord then plug a
chip into ~ gently pry out each of the pins from the plastic inclosure ~ then
soder to the pin instead of directly to the chip ~ then plug the pin onto the
corrisponding chip pin ~ when all is sodered togeather it roughly has the
same rigidity without transfering the heat to the chip and damageing it.
9631 Sun, 30 Jan 2000 11:23:02 -0800 [alt-beam] Re: Electronic Nomenclature question beam@sgiblab.sgi.com Bruce Robinson David Stafford wrote:
>
> Can anyone tell me some general guidelines ...
> for figuring out what a chip does by its number?
I'll be very interested to see what everyone else does ...
Personally, I keep on hand a Jameco catalogue (any old one will do)
which has, in the front, a list of the IC chips they sell. They list the
chips in different categories (e.g. 74HC00D series), giving the chip
number, number of pins, and a brief, single line description, along with
their selling price.
This is enough to give me an idea if the chip is one that might be
useful for my purposes. When I find one I'm interested in, I visit
Motorola's web site:
http://mot-sps.com/products/index.html
They keep reorganizing the site ... here is the current path to get to
the useful part: From the products page,
- click on "Logic" (way down at the bottom of the page)
- then click on "Product Families" (top of the logic list)
- finally click on the Product family you're interested in
(I usually start with "HC").
That will give you a list of chips, along with their short descriptions.
You can click on any chip number to get details, and you can
read/download specific datasheets in Adobe Acrobat format.
Many of the logic chips we use are in the 74 series, which are typically
numbered as follows:
MC74HC14AN
MC = manufacturer code (varies ... MC is Motorola's code)
74 = chip series
HC = chip family (varies ... see below)
14 = function (14 = Hex Schmitt trigger)
A = manufacturer's designation (optional)
N = package type (varies ... N = Dual Inline Pin)
Dane Gardner has given a much better description of the chip families
than I could come up with.
Watch out for the package type: usually you want:
type N = dual inline pin, plastic case.
type J = dual inline pin, ceramic case.
Other package types are for surface mount packages, that are much, much
smaller.
The key number is the function, and that's what the description in the
Jameco catalog / Motorola web site / other web sites will tell you
about.
Regards,
Bruce
9632 Sun, 30 Jan 2000 14:23:48 -0500 [alt-beam] Re: FreeFormingBicore question "Dennison Bertram" As a little freeforming tip, when I free form, I usually lay the chip with
it's back down on a damp spong, water is a very good absorber of heat.
That's why you can put a match out on your tounge if it's wet enough.
dennison
In a message dated 1/30/2000 12:29:23 PM Eastern Standard Time,
phillip@ryals.com writes:
<< All I'm left with now, is perhaps that I ruined the chip with heat. >>
I might ask this ~ did you soder directly to the terminals of the 74 chip??
If you did then you made your first mistake ~ I have burnt up a lot of chips
this way myself ~ most chips cannot take this heat of free forming like is
shown in the webpages of other peoples bots. ~ with practice and a little
bit
of time ~ and with very low heat soder iron ~ heat sink clips, etc. ~ you
will be able to get this done with out damaging the chip ~ but........... I
have a better suggestion for you:
Take a simple IC socket that you would soder to a circuit bord then plug a
chip into ~ gently pry out each of the pins from the plastic inclosure ~
then
soder to the pin instead of directly to the chip ~ then plug the pin onto
the
corrisponding chip pin ~ when all is sodered togeather it roughly has the
same rigidity without transfering the heat to the chip and damageing it.
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