Thank you for welcoming me as a member of your group
Electronics_101

Regards,
Benjie

__________________________________________________
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IF you can find October Nuts and Volts magazine, there is an article
that would fit the bill exactly, and more importantly... Cheap.



LAMP CONTROL WITH YOUR STAMP - Jerry Reed
Get some bright ideas with this simple "contractor's delight" set-up
that works not only with a BS2 OEM board, but will interface with a
PC parallel port or other digital outputs, as well.


Tim


--- In Electronics_101@y..., yahoo@c... wrote:

I am working on a circut which uses a EEPROM made by Parallax to
animate a string of christmas type lights. I intend to have four
separate 120vac outlets that are switched on and off (dimming would
be nice) by the EEPROM. Obviously, the outputs EEPROM can not

handle

much current at all. I thought of using the EEPROM to control a

small

relay and hook the contacts of the small relay to a coil of a

larger

relay to turn the light on and off, but I would like to use some

kind

of solid state circut to control the 120vac (that way I could
implement dimming). Any thoughts on how I can control the 120vac

with

a small current. Sorry I don't know the exact peak current the
outputs on the EEPROM can handle.

__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.

I am working on a circut which uses a EEPROM made by Parallax to
animate a string of christmas type lights. I intend to have four
separate 120vac outlets that are switched on and off (dimming would
be nice) by the EEPROM. Obviously, the outputs EEPROM can not handle
much current at all. I thought of using the EEPROM to control a small
relay and hook the contacts of the small relay to a coil of a larger
relay to turn the light on and off, but I would like to use some kind
of solid state circut to control the 120vac (that way I could
implement dimming). Any thoughts on how I can control the 120vac with
a small current. Sorry I don't know the exact peak current the
outputs on the EEPROM can handle.

__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.

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开云体育

----- Original Message -----

From: Sudhaker Raj

To: Electronics_101@...

Sent: Tuesday, October 23, 2001 11:31 AM

Subject: [Electronics_101] Re: Switching and Dimming 120vac

I wana to add something from my earlier experience.

you should use pulse mode trigering for turning on the triac that way
it can handle. say pulse train of 2kHz with 10% duty cycle will be
great. use some transister as 2N2222 to power up the triac
triggering...

?? ?Actually, I was thinking along the same lines, using a 2N2222 to trigger a triac, so thank you for your input there. The opto isolators are an ideal I did not think of before but are definatly a good ideal.

as JIM said, EEPROM is not for that kind of circuitary. guess true, u
can always avoid this by a single decade counter chip with de-
mutiplxed output (10 seperate output changing state one by one) and
wire it for your desired sequence. why to use momory when U can build
this 3 or 4 bit memory by wires (hee hee...)... also U r not going to
program it very often, it will be one time JOB...

?

??? The pattern is not as simple as lights flashing in sequence, and the exact pattern may vary and have more than one light on at a time. I am making several of these circuts and?I have designed them to be programmable?by a user with no electronics knowlage. They can hook it to their computer and set a pattern for the lights using software I wrote. After the pattern is sent to the box, the computer can be disconected and the circut runs on its own. Curently, the circut controls LED's so I can see what was going on as I write the software.

OPTO-ISOLATOR is a great idea if u r willing to interface the DC
circuit with some other device... but if U want to make the whole
system stand alone, u can surely avoid them to make whole setup
cheaper...

---
Raj
--- In Electronics_101@y..., Jim Purcell wrote:
> yahoo,
>
> > I am working on a circut which uses a EEPROM made by Parallax to
> > animate a string of christmas type lights. I intend to have four
> > separate 120vac outlets that are switched on and off (dimming
would
> > be nice) by the EEPROM. Obviously, the outputs EEPROM can not
handle
> > much current at all.
>
> Memories of any kind are not designed to drive anything but other
circuits.
> In addition digital devices won't like AC. What you will need is a
triac for
> each AC device. In addition I would use opto isolators to couple the
> controlling signals to the triacs and probably buffers to control
the opto
> isolators.? An opto isolator is a device that uses some kind of
light source,
> usually LED's to turn on and off another device, like a transistor
or a
> triac, etc.? A buffer is a device that draws very little current
from the
> input device but can deliver larger current to the output device.
>
> Jim
>
> > I thought of using the EEPROM to control a small
> > relay and hook the contacts of the small relay to a coil of a
larger
> > relay to turn the light on and off, but I would like to use some
kind
> > of solid state circut to control the 120vac (that way I could
> > implement dimming). Any thoughts on how I can control the 120vac
with
> > a small current. Sorry I don't know the exact peak current the
> > outputs on the EEPROM can handle.
> >
> >
> > To unsubscribe from this group, send an email to:
> > Electronics_101-unsubscribe@y...
> >
> >
> >
> > Your use of Yahoo! Groups is subject to

To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...



Your use of Yahoo! Groups is subject to the .

just between you and me,i was staying in a hotel and took apart their phone *the kind with a credit card reader slot*,and took the reader out,is there anything useful i can do with it?how would i go about hookin it up to a computer?i dont know much about electronics,email me at linuxgeek@...

Charles,

Reading from mag stripe cards is easy - but first you need to know what you
are reading - there are several different formats and several different
track types / numbers / protocols / formats, then you need the appropriate
head type to read what you need. USB is very difficult - and very very
expensive ... not a $10-00 job ... more like a $1000-00 job - just for the
development kit.

Writing mag stripe cards is not particularly difficult - however you need
the appropriate write head with the needed number of tracks on it and the
driver circuit to go along with it (also not that hard) ... you then need to
control the precise speed in which the track is written.

Or you could use a serial buffer IC with the clock input deriving from an
optocoder connected to say a rubber wheel that moves as the card goes
through the writer. Depends what you want to use it for.


J0n

Everything has a static charge.

Try this link. It explains it pretty well.

Sudhaker,

OPTO-ISOLATOR is a great idea if u r willing to interface the DC
circuit with some other device... but if U want to make the whole
system stand alone, u can surely avoid them to make whole setup
cheaper...

Cheaper yes but when 'talking' to 120 VAC power line safety is another
factor. As for the pulsing the devices, depending on what kind of controls
are used they'd be pulsed anyway. The program would run in a loop and pulse
each device with whatever it's supposed to be, on or off.
The rate would depend on the clock rate.

Jim

Hello all,
I'm new to this group, and have a special project .. was hoping I
could find some people to point me in the right direction.

I am building a magnetic strip reader / writer, and although I have
come across some very crude plans, I do not have access to any of the
parts that it ask for, or requires, and was wondering if there was a
way to take standard read write heads, and use them for this purpose,
and if you could find the circuit and plans needed to construct it.
Basicly, I want to be able to strole into Rat Shack, pop down 10
bucks, and come out with everything I need to build this lil unit,
with a serial, or better yet, a USB port so I can read the cards from
a computer, as well as write to them. Sounds like a fun project to me.

Get in touch with me at hazenoff@... if you have any info on a
project like this..

Tim,

Actually, there are no MOS transistors anymore ... metal has not been
the the conductor above the oxide for nearly 15 years in advanced
processes.

Yet they still use the term CMOS which stands for complimentary metal oxide
semiconductor.

Jim

Hello,

I also am new here. I love electronics, have been involved in
electricity and electronics as a hobbist as a young kid. I don't have
alot of experiance constructing my own things, but like to learn, and
am willing to share what I know.

Joe & Monty Hansen ICQ 47446680

I love cats !!


--- In Electronics_101@y..., Tavys Ashcroft <bigtex@c...> wrote:

Hi, I just joined this group. I was actually thinking of starting

my

own, but I found this one. I'm taking electronics classes and
learning a lot, but have found very little tutorial information
online that I find useful.

yahoo,

I am working on a circut which uses a EEPROM made by Parallax to
animate a string of christmas type lights. I intend to have four
separate 120vac outlets that are switched on and off (dimming would
be nice) by the EEPROM. Obviously, the outputs EEPROM can not handle
much current at all.

Memories of any kind are not designed to drive anything but other circuits.
In addition digital devices won't like AC. What you will need is a triac for
each AC device. In addition I would use opto isolators to couple the
controlling signals to the triacs and probably buffers to control the opto
isolators. An opto isolator is a device that uses some kind of light source,
usually LED's to turn on and off another device, like a transistor or a
triac, etc. A buffer is a device that draws very little current from the
input device but can deliver larger current to the output device.

Jim

I thought of using the EEPROM to control a small
relay and hook the contacts of the small relay to a coil of a larger
relay to turn the light on and off, but I would like to use some kind
of solid state circut to control the 120vac (that way I could
implement dimming). Any thoughts on how I can control the 120vac with
a small current. Sorry I don't know the exact peak current the
outputs on the EEPROM can handle.


To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...



Your use of Yahoo! Groups is subject to

linux,

just between you and me,i was staying in a hotel and took apart their phone *the kind with a credit card reader slot*,and took the reader out,is there anything useful i can do with it?

Are you expecting us to participate in your theft by helping you make what you stole worth something?

Jim

epsulon,

Everything has a static charge.

Not so, not even every atomic particle. Neutrons have no charge. Metals and
other conductors can conduct current but cannot normally be charged. Only
insulators can be charged. What gives something a charge is the loss or gain
of electrons. Insulators can become charged and because they do not conduct
they may retain the charge. And most objects are neutral.

Jim

Jim wrote:

--- In Electronics_101@y..., Jim Purcell <jpurcell@w...> wrote:

living,

I need to record on three hand held cassette recorders from

another

so as to make three copies at one time. I once found a circuit

that

would allow me to do that on the Net, but nave lost it. Does

anyone

have such a circuit, or tell me where to find one?

Tape recorder microphones used to be high impedance, I'm not sure

what

impedance they are these days, but probably fairly high. Are you

recording

the three machines from the earphone output of another? The

earphone output

is low impedance so you can probably connect all three cassette mic

inputs

together with no problem. Try it, you may like it. :-)

I plan to use the earphone output as you say, Jim. But the circuit I
saw had some kind of splitter, fairly common I understand, but
somethign you would buy at an electronics shop, not in the consumer
electronics department of a department store. I know very little
about electronics, so don't know how to connect these using the
splitter or what ever it is. Any help you could give me a schematic
or something might help me accomplish it.

Thank you for your valuable time and help, Jim.

Best Regards,
Don

Don A. Herrington
Cebu City, Philippines
Where the Mountains Meet the Sea
In the Land of Smiles
www.geocities.com/livinginthephilippines/index.html
Home of the "Living in the Philippines" list for Expats

Jim

--- In Electronics_101@y..., beagle22000@y... wrote:

Hi! Would anyone like to give a brief description of how the work-
electrical principles etc? Thanks.

I would guess it uses a charge pump to increase the voltage to about
5000V and then discharges through the pin and through your body and
to ground ?!?!? Noy sure though

-Mounir