Uln2003a
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Posts: 46,084
I am interfacing the ULN2003A to the basic stamp. Does anyone know
if I can connect all of the inputs together and connect all of the
outputs together. What I am trying to do is switch a load that is
about 2 amps. If the ULN2003A is configured this way it will supply
a maximum current of 3.5 amps but I don't know if it's correct to do
this. If not, does anyone have any ideas to switch 2 amps without
using a relay?
Thanks,
Chris
if I can connect all of the inputs together and connect all of the
outputs together. What I am trying to do is switch a load that is
about 2 amps. If the ULN2003A is configured this way it will supply
a maximum current of 3.5 amps but I don't know if it's correct to do
this. If not, does anyone have any ideas to switch 2 amps without
using a relay?
Thanks,
Chris
Comments
http://www.geocities.com/jimforkin2003/
jim
Original Message
From: christopher41877 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=wDiJEMJbZc79Ay0SEH-VC_Km6113wGHaIsVLdozNiWt-V0wAZAs1hsDhnvv-qRtZPJQ1JmYYBJbVYD-ClP7P5vz6Lw]CHRIS@R...[/url
Sent: Tuesday, May 06, 2003 6:49 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] ULN2003A
I am interfacing the ULN2003A to the basic stamp. Does anyone know
if I can connect all of the inputs together and connect all of the
outputs together. What I am trying to do is switch a load that is
about 2 amps. If the ULN2003A is configured this way it will supply
a maximum current of 3.5 amps but I don't know if it's correct to do
this. If not, does anyone have any ideas to switch 2 amps without
using a relay?
Thanks,
Chris
To UNSUBSCRIBE, just send mail to:
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Have a look in the TI ULN2003A datasheet available through Digikey.
Figure 18 is a "Buffer for Higher Current Loads".
This would be a much better way to handle higher loads.
I'm no expert, but hooking all the ULN2003A inputs to a single BS output
probably isn't wise. Besides, using a power transistor is much more
elegant.
Cheers,
Dave
Original Message
From: christopher41877 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=0zIr5BY7xNe_wF6zkV4w99frj9rcXmGlRge44DB8YhK-UXc82AoUO3q5j_iHmwyGE2cfTy90wVhVJ2wGhNWwMqwcw0Bm0g]CHRIS@R...[/url
Sent: Tuesday, May 06, 2003 6:49 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] ULN2003A
I am interfacing the ULN2003A to the basic stamp. Does anyone know
if I can connect all of the inputs together and connect all of the
outputs together. What I am trying to do is switch a load that is
about 2 amps. If the ULN2003A is configured this way it will supply
a maximum current of 3.5 amps but I don't know if it's correct to do
this. If not, does anyone have any ideas to switch 2 amps without
using a relay?
Thanks,
Chris
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.
Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
CHRIS@R... writes:
> I am interfacing the ULN2003A to the basic stamp. Does anyone know
> if I can connect all of the inputs together and connect all of the
> outputs together. What I am trying to do is switch a load that is
> about 2 amps. If the ULN2003A is configured this way it will supply
> a maximum current of 3.5 amps but I don't know if it's correct to do
> this. If not, does anyone have any ideas to switch 2 amps without
> using a relay?
>
> Thanks,
>
> Chris
>
Do you want to switch power or ground? A Mosfet will easily do a nice job of
switching 10's of amps....
[noparse][[/noparse]Non-text portions of this message have been removed]
the high current. Since I am not as familiar with them as I should
be, if I get an N-Channel mosfet, does that mean I turn it on with a
low, or does the output supply ground, or can I configure it any way
I want. I would like to switch +12V but I know that using ground it
can supply more.
Chris
--- In basicstamps@yahoogroups.com, smartdim@a... wrote:
> In a message dated 5/6/2003 3:50:56 AM Pacific Daylight Time,
> CHRIS@R... writes:
>
> > I am interfacing the ULN2003A to the basic stamp. Does anyone
know
> > if I can connect all of the inputs together and connect all of
the
> > outputs together. What I am trying to do is switch a load that
is
> > about 2 amps. If the ULN2003A is configured this way it will
supply
> > a maximum current of 3.5 amps but I don't know if it's correct
to do
> > this. If not, does anyone have any ideas to switch 2 amps
without
> > using a relay?
> >
> > Thanks,
> >
> > Chris
> >
>
> Do you want to switch power or ground? A Mosfet will easily do a
nice job of
> switching 10's of amps....
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
A N-channel MOSFET with logic-level gate voltage would work great. The
logic-level gate voltage means that it will turn on fully with the 5V output
of a Stamp or other microcontroller. Standard MOSFETs need more gate
voltage for full turn on. You would turn on the N-channel MOSFET with a
"high" from your Stamp pin.
Using a N-channel MOSFET, you would connect it between your load and ground,
with the other side of the load connected to B+. (Much like a common NPN
switching transistor.) The IRL520 by International Rectifier would work
well for your application -- it's rated for up to 10 amps, and up to 100V B+
supply. They are .68 each at the link below, with very inexpensive
shipping. (Yes, I admit it -- that's me ;-) The IRL530 and 540 are also
nice if you want a device with even lower on resistance and a higher max
current rating.
Using a couple resistors connected to the MOSFET gate is a good idea, but
not absolutely necessary in every situation...
When your circuit first powers up, it takes the Stamp a moment to begin
executing your code. During that time the Stamp pin connected to the MOSFET
is an input, and is "floating" -- which means that electrical "noise" might
make the MOSFET turn on. Once your Stamp software makes the pin an output,
this is usually no longer an issue. To prevent the MOSFET from turning on
during the power up time (if it would be a problem), you can connect a
"pull-down" resistor between the MOSFET gate and ground. Something in the
range of 1k to 10k ohms would be fine.
It is also considered good practice to connect a 50 to 100 ohm resistor
between the Stamp pin and the MOSFET gate, as close to the gate as possible.
That helps prevent unwanted oscillation of the MOSFET. You will see some
circuits that don't show this resistor, but considering the low cost of
resistors it's a good thing to do. I sometimes don't bother with it when
"tinkering" on a breadboard, but always include it when building a project
that I'd like to work reliably.
Randy
www.glitchbuster.com
Original Message
From: "christopher41877" <CHRIS@R...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, May 06, 2003 8:42 AM
Subject: [noparse][[/noparse]basicstamps] Re: ULN2003A
> Thanks guys, it looks like a mosfet will be the best idea because of
> the high current. Since I am not as familiar with them as I should
> be, if I get an N-Channel mosfet, does that mean I turn it on with a
> low, or does the output supply ground, or can I configure it any way
> I want. I would like to switch +12V but I know that using ground it
> can supply more.
>
> Chris
>
>
>
> --- In basicstamps@yahoogroups.com, smartdim@a... wrote:
> > In a message dated 5/6/2003 3:50:56 AM Pacific Daylight Time,
> > CHRIS@R... writes:
> >
> > > I am interfacing the ULN2003A to the basic stamp. Does anyone
> know
> > > if I can connect all of the inputs together and connect all of
> the
> > > outputs together. What I am trying to do is switch a load that
> is
> > > about 2 amps. If the ULN2003A is configured this way it will
> supply
> > > a maximum current of 3.5 amps but I don't know if it's correct
> to do
> > > this. If not, does anyone have any ideas to switch 2 amps
> without
> > > using a relay?
> > >
> > > Thanks,
> > >
> > > Chris
> > >
> >
> > Do you want to switch power or ground? A Mosfet will easily do a
> nice job of
> > switching 10's of amps....
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> 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.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
You provided some great information. I have just one more question.
I know how NPN and PNP transistors work, are these the same? I just
need to know where to connect my load (i.e Drain, source) and where
to connect my supply ground and I would assume that I connect the
output of the basic stamp to the gate. So an N-Channel MOSFET simply
means that it switches just like an NPN transistor, is this correct?
--- In basicstamps@yahoogroups.com, "Randy Jones" <randyjones@w...>
wrote:
> Hi Chris,
>
> A N-channel MOSFET with logic-level gate voltage would work great.
The
> logic-level gate voltage means that it will turn on fully with the
5V output
> of a Stamp or other microcontroller. Standard MOSFETs need more
gate
> voltage for full turn on. You would turn on the N-channel MOSFET
with a
> "high" from your Stamp pin.
>
> Using a N-channel MOSFET, you would connect it between your load
and ground,
> with the other side of the load connected to B+. (Much like a
common NPN
> switching transistor.) The IRL520 by International Rectifier would
work
> well for your application -- it's rated for up to 10 amps, and up
to 100V B+
> supply. They are .68 each at the link below, with very inexpensive
> shipping. (Yes, I admit it -- that's me ;-) The IRL530 and 540
are also
> nice if you want a device with even lower on resistance and a
higher max
> current rating.
>
> Using a couple resistors connected to the MOSFET gate is a good
idea, but
> not absolutely necessary in every situation...
>
> When your circuit first powers up, it takes the Stamp a moment to
begin
> executing your code. During that time the Stamp pin connected to
the MOSFET
> is an input, and is "floating" -- which means that
electrical "noise" might
> make the MOSFET turn on. Once your Stamp software makes the pin an
output,
> this is usually no longer an issue. To prevent the MOSFET from
turning on
> during the power up time (if it would be a problem), you can
connect a
> "pull-down" resistor between the MOSFET gate and ground. Something
in the
> range of 1k to 10k ohms would be fine.
>
> It is also considered good practice to connect a 50 to 100 ohm
resistor
> between the Stamp pin and the MOSFET gate, as close to the gate as
possible.
> That helps prevent unwanted oscillation of the MOSFET. You will
see some
> circuits that don't show this resistor, but considering the low
cost of
> resistors it's a good thing to do. I sometimes don't bother with
it when
> "tinkering" on a breadboard, but always include it when building a
project
> that I'd like to work reliably.
>
> Randy
>
> www.glitchbuster.com
>
>
>
>
Original Message
> From: "christopher41877" <CHRIS@R...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, May 06, 2003 8:42 AM
> Subject: [noparse][[/noparse]basicstamps] Re: ULN2003A
>
>
> > Thanks guys, it looks like a mosfet will be the best idea because
of
> > the high current. Since I am not as familiar with them as I
should
> > be, if I get an N-Channel mosfet, does that mean I turn it on
with a
> > low, or does the output supply ground, or can I configure it any
way
> > I want. I would like to switch +12V but I know that using ground
it
> > can supply more.
> >
> > Chris
> >
> >
> >
> > --- In basicstamps@yahoogroups.com, smartdim@a... wrote:
> > > In a message dated 5/6/2003 3:50:56 AM Pacific Daylight Time,
> > > CHRIS@R... writes:
> > >
> > > > I am interfacing the ULN2003A to the basic stamp. Does anyone
> > know
> > > > if I can connect all of the inputs together and connect all of
> > the
> > > > outputs together. What I am trying to do is switch a load
that
> > is
> > > > about 2 amps. If the ULN2003A is configured this way it will
> > supply
> > > > a maximum current of 3.5 amps but I don't know if it's correct
> > to do
> > > > this. If not, does anyone have any ideas to switch 2 amps
> > without
> > > > using a relay?
> > > >
> > > > Thanks,
> > > >
> > > > Chris
> > > >
> > >
> > > Do you want to switch power or ground? A Mosfet will easily do a
> > nice job of
> > > switching 10's of amps....
> > >
> > >
> > > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> > 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.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
saturated switch connected to the ground side of your load. The MOSFET
source would be connected to ground (like the NPN emitter), and the drain
would be connected to one side of your load (like the NPN collector). The
other side of the load would be connected to B+.
As you mentioned, the gate is connected to the Stamp pin (preferably using
the two resistors I mentioned previously.
Randy
www.glitchbuster.com
> Thanks Randy,
>
> You provided some great information. I have just one more question.
> I know how NPN and PNP transistors work, are these the same? I just
> need to know where to connect my load (i.e Drain, source) and where
> to connect my supply ground and I would assume that I connect the
> output of the basic stamp to the gate. So an N-Channel MOSFET simply
> means that it switches just like an NPN transistor, is this correct?
>
>
>
> --- In basicstamps@yahoogroups.com, "Randy Jones" <randyjones@w...>
> wrote:
> > Hi Chris,
> >
> > A N-channel MOSFET with logic-level gate voltage would work great.
> The
> > logic-level gate voltage means that it will turn on fully with the
> 5V output
> > of a Stamp or other microcontroller. Standard MOSFETs need more
> gate
> > voltage for full turn on. You would turn on the N-channel MOSFET
> with a
> > "high" from your Stamp pin.
> >
> > Using a N-channel MOSFET, you would connect it between your load
> and ground,
> > with the other side of the load connected to B+. (Much like a
> common NPN
> > switching transistor.) The IRL520 by International Rectifier would
> work
> > well for your application -- it's rated for up to 10 amps, and up
> to 100V B+
> > supply. They are .68 each at the link below, with very inexpensive
> > shipping. (Yes, I admit it -- that's me ;-) The IRL530 and 540
> are also
> > nice if you want a device with even lower on resistance and a
> higher max
> > current rating.
> >
> > Using a couple resistors connected to the MOSFET gate is a good
> idea, but
> > not absolutely necessary in every situation...
> >
> > When your circuit first powers up, it takes the Stamp a moment to
> begin
> > executing your code. During that time the Stamp pin connected to
> the MOSFET
> > is an input, and is "floating" -- which means that
> electrical "noise" might
> > make the MOSFET turn on. Once your Stamp software makes the pin an
> output,
> > this is usually no longer an issue. To prevent the MOSFET from
> turning on
> > during the power up time (if it would be a problem), you can
> connect a
> > "pull-down" resistor between the MOSFET gate and ground. Something
> in the
> > range of 1k to 10k ohms would be fine.
> >
> > It is also considered good practice to connect a 50 to 100 ohm
> resistor
> > between the Stamp pin and the MOSFET gate, as close to the gate as
> possible.
> > That helps prevent unwanted oscillation of the MOSFET. You will
> see some
> > circuits that don't show this resistor, but considering the low
> cost of
> > resistors it's a good thing to do. I sometimes don't bother with
> it when
> > "tinkering" on a breadboard, but always include it when building a
> project
> > that I'd like to work reliably.
> >
> > Randy
> >
> > www.glitchbuster.com
> >
> >
> >
> >
Original Message
> > From: "christopher41877" <CHRIS@R...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, May 06, 2003 8:42 AM
> > Subject: [noparse][[/noparse]basicstamps] Re: ULN2003A
> >
> >
> > > Thanks guys, it looks like a mosfet will be the best idea because
> of
> > > the high current. Since I am not as familiar with them as I
> should
> > > be, if I get an N-Channel mosfet, does that mean I turn it on
> with a
> > > low, or does the output supply ground, or can I configure it any
> way
> > > I want. I would like to switch +12V but I know that using ground
> it
> > > can supply more.
> > >
> > > Chris
> > >
> > >
> > >
> > > --- In basicstamps@yahoogroups.com, smartdim@a... wrote:
> > > > In a message dated 5/6/2003 3:50:56 AM Pacific Daylight Time,
> > > > CHRIS@R... writes:
> > > >
> > > > > I am interfacing the ULN2003A to the basic stamp. Does anyone
> > > know
> > > > > if I can connect all of the inputs together and connect all of
> > > the
> > > > > outputs together. What I am trying to do is switch a load
> that
> > > is
> > > > > about 2 amps. If the ULN2003A is configured this way it will
> > > supply
> > > > > a maximum current of 3.5 amps but I don't know if it's correct
> > > to do
> > > > > this. If not, does anyone have any ideas to switch 2 amps
> > > without
> > > > > using a relay?
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Chris
> > > > >
> > > >
> > > > Do you want to switch power or ground? A Mosfet will easily do a
> > > nice job of
> > > > switching 10's of amps....
> > > >
> > > >
> > > > [noparse][[/noparse]Non-text portions of this message have been removed]
> > >
> > >
> > > 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.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> > >
>
>
> 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.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>