Are buffers ( CMOS 4050 etc) any use to protect the stamp''s outputs???
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Posts: 46,084
Arrhid,
The ULN2003 can be connected directly to the Stamp pins. It has a built in
current limiting resistor, so no external one is needed. It also has a
protection diode in case you are running and inductive load, like a relay,
to protect it from spikes.
The ULN2003 can easily handle 500mA. I think it might be able to do it on
one pin, I can't seem to find the spec sheet right now. If one pin can't
handle it, you can hook up outputs in series for more current capabilty.
Jonathan
www.madlabs.info
Original Message
From: "arridh_shashank" <arridh_shashank@y...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, December 29, 2003 6:47 AM
Subject: [noparse][[/noparse]basicstamps] Re: Are buffers ( CMOS 4050 etc) any use to protect
the stamp's outputs???
> Hi Jon
>
> So all I would need to do to protect my stamp from excessive current
> sourcing would be to add 220 Ohm resistors in series? Can I then
> connect a ULN2803 or should I leave out the 220 Ohm if I am
> connecting it? Also what is the maximum current a 2803 would source
> from the stamp to drive its maximum 500 milli amp Load? I have been
> unable to work this out.
>
> Many thanks
> Arridh
>
>
>
>
> --- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
> wrote:
> > If you're simply looking to protect your Stamp you can put 220 ohm
> > resistors in series with your outputs; we do this on the Homework
> Board
> > (BS2) and BS1 Project Board -- both boards are designed for
> students.
> > You may want to consider buffers if you need more current than the
> Stamp
> > can safely sink or source.
> >
> > -- Jon Williams
> > -- Applications Engineer, Parallax
> > -- Dallas Office
> >
> >
> >
Original Message
> > From: arridh_shashank [noparse][[/noparse]mailto:arridh_shashank@y...]
> > Sent: Monday, December 29, 2003 1:36 AM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] Are buffers ( CMOS 4050 etc) any use to
> protect
> > the stamp's outputs???
> >
> >
> > Hey
> >
> > I'm not sure my self if this will work or not so I thought I'd ask
> > you guys [noparse]:D[/noparse]. I wanted to protect my stamp outputs from gettin
> > damaged by sourcing and sinking too much current so I looked
> around
> > and found the cmos 4050 chip non inverting hex buffer. I was
> > wondering if it will protect my stamp from sourcing and sinking a
> > lot of current. What I plan to do is to use it as a intermediate
> > between my stamp and my output device so as to protect the stamp.
> > Would this be a benifitial setup to have and is this the use the
> > chip was developed for? Furthermore will it protect my stamp from
> > damage in the instance that a large base current was drawn by a
> > transistor or similar instance? Any light you guys can shed on the
> > subject would be helpful.
> >
> > Many thanks
> > Arridh
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
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> Subject
> > and Body of the message will be ignored.
> >
> >
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> >
> > To visit your group on the web, go to:
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> >
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> >
> >
> >
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>
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>
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>
> To visit your group on the web, go to:
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>
>
>
The ULN2003 can be connected directly to the Stamp pins. It has a built in
current limiting resistor, so no external one is needed. It also has a
protection diode in case you are running and inductive load, like a relay,
to protect it from spikes.
The ULN2003 can easily handle 500mA. I think it might be able to do it on
one pin, I can't seem to find the spec sheet right now. If one pin can't
handle it, you can hook up outputs in series for more current capabilty.
Jonathan
www.madlabs.info
Original Message
From: "arridh_shashank" <arridh_shashank@y...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, December 29, 2003 6:47 AM
Subject: [noparse][[/noparse]basicstamps] Re: Are buffers ( CMOS 4050 etc) any use to protect
the stamp's outputs???
> Hi Jon
>
> So all I would need to do to protect my stamp from excessive current
> sourcing would be to add 220 Ohm resistors in series? Can I then
> connect a ULN2803 or should I leave out the 220 Ohm if I am
> connecting it? Also what is the maximum current a 2803 would source
> from the stamp to drive its maximum 500 milli amp Load? I have been
> unable to work this out.
>
> Many thanks
> Arridh
>
>
>
>
> --- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
> wrote:
> > If you're simply looking to protect your Stamp you can put 220 ohm
> > resistors in series with your outputs; we do this on the Homework
> Board
> > (BS2) and BS1 Project Board -- both boards are designed for
> students.
> > You may want to consider buffers if you need more current than the
> Stamp
> > can safely sink or source.
> >
> > -- Jon Williams
> > -- Applications Engineer, Parallax
> > -- Dallas Office
> >
> >
> >
Original Message
> > From: arridh_shashank [noparse][[/noparse]mailto:arridh_shashank@y...]
> > Sent: Monday, December 29, 2003 1:36 AM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] Are buffers ( CMOS 4050 etc) any use to
> protect
> > the stamp's outputs???
> >
> >
> > Hey
> >
> > I'm not sure my self if this will work or not so I thought I'd ask
> > you guys [noparse]:D[/noparse]. I wanted to protect my stamp outputs from gettin
> > damaged by sourcing and sinking too much current so I looked
> around
> > and found the cmos 4050 chip non inverting hex buffer. I was
> > wondering if it will protect my stamp from sourcing and sinking a
> > lot of current. What I plan to do is to use it as a intermediate
> > between my stamp and my output device so as to protect the stamp.
> > Would this be a benifitial setup to have and is this the use the
> > chip was developed for? Furthermore will it protect my stamp from
> > damage in the instance that a large base current was drawn by a
> > transistor or similar instance? Any light you guys can shed on the
> > subject would be helpful.
> >
> > Many thanks
> > Arridh
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> Subject
> > and Body of the message will be ignored.
> >
> >
> > Yahoo! Groups Links
> >
> > To visit your group on the web, go to:
> > http://groups.yahoo.com/group/basicstamps/
> >
> > To unsubscribe from this group, send an email to:
> > basicstamps-unsubscribe@yahoogroups.com
> >
> > Your use of Yahoo! Groups is subject to:
> > http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
> > This message has been scanned by WebShield. Please report SPAM to
> > abuse@p...
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Yahoo! Groups Links
>
> To visit your group on the web, go to:
> http://groups.yahoo.com/group/basicstamps/
>
> To unsubscribe from this group, send an email to:
> basicstamps-unsubscribe@yahoogroups.com
>
> Your use of Yahoo! Groups is subject to:
> http://docs.yahoo.com/info/terms/
>
>
>
>