Stamp Outputs
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Posts: 46,084
Hi: Maybe this has been answered before but a little digging around
didn't uncover it . . . I see the output pins are 20 ma each
sourcing, 50ma total on a bank, 50ma total with the internal voltage
supply. So if I want to drive a few of those nifty SCR's that
requires 15ma I might run out of current real quick. So I'm thinking
of putting a 2N2222 npn device between them. Is that the way to go
or is there another solution for this?
Thanks . . . John.
didn't uncover it . . . I see the output pins are 20 ma each
sourcing, 50ma total on a bank, 50ma total with the internal voltage
supply. So if I want to drive a few of those nifty SCR's that
requires 15ma I might run out of current real quick. So I'm thinking
of putting a 2N2222 npn device between them. Is that the way to go
or is there another solution for this?
Thanks . . . John.
Comments
Especially with SCR's and Triacs and such.
Original Message
From: jrem123 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=oTRVYyiROq2DUFzfUyEkkal0yxhGes9CS4NzN5L3XGrQJgEGujt8FUliRWG6DcqjxNGfCeDoIvQ]jrem123@y...[/url
Sent: Monday, June 17, 2002 4:02 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Stamp Outputs
Hi: Maybe this has been answered before but a little digging around
didn't uncover it . . . I see the output pins are 20 ma each
sourcing, 50ma total on a bank, 50ma total with the internal voltage
supply. So if I want to drive a few of those nifty SCR's that
requires 15ma I might run out of current real quick. So I'm thinking
of putting a 2N2222 npn device between them. Is that the way to go
or is there another solution for this?
Thanks . . . John.
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Don
Original Message
From: "jrem123" <jrem123@y...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, June 17, 2002 2:01 PM
Subject: [noparse][[/noparse]basicstamps] Stamp Outputs
> Hi: Maybe this has been answered before but a little digging around
> didn't uncover it . . . I see the output pins are 20 ma each
> sourcing, 50ma total on a bank, 50ma total with the internal voltage
> supply. So if I want to drive a few of those nifty SCR's that
> requires 15ma I might run out of current real quick. So I'm thinking
> of putting a 2N2222 npn device between them. Is that the way to go
> or is there another solution for this?
>
> Thanks . . . John.
>
>
> 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/
>
>
>
IT IS PNPN DEVICE WITH THREE TERMINALS (ANODE, CATHODE, AND GATE) THAT ACTS LIKE
A SWITCH. WHEN ENOUGH CURRENT REACHES THE GATE THE ANODE AND CATHODE WILL
CONDUCT ASSUMING THE CATHODE IS NEGATIVE WITH RESPECT TO THE ANODE. THEY HAVE
VERY LOW DYNAMIC RESISTANCE AND CAN SWITCH VERY LARGE AMOUNTS OF CURRENT
>400AMPS
GOOD LUCK!
-=RANDY KNUTSON
Don <renegade.engineer@v...> wrote: SCR's? Help on the acronym please.
Don
Original Message
From: "jrem123"
To:
Sent: Monday, June 17, 2002 2:01 PM
Subject: [noparse][[/noparse]basicstamps] Stamp Outputs
> Hi: Maybe this has been answered before but a little digging around
> didn't uncover it . . . I see the output pins are 20 ma each
> sourcing, 50ma total on a bank, 50ma total with the internal voltage
> supply. So if I want to drive a few of those nifty SCR's that
> requires 15ma I might run out of current real quick. So I'm thinking
> of putting a 2N2222 npn device between them. Is that the way to go
> or is there another solution for this?
>
> Thanks . . . John.
>
>
> 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/
>
>
>
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[noparse][[/noparse]Non-text portions of this message have been removed]
SCR stands for "Silicon Controlled Rectifier". Think of it as a high current
diode, that
you can cause to conduct whenever you like, otherwise it's in its "blocking"
state, and
only a very small leakage current will flow. It will provide half-wave power
for AC circuits.
You can use it for DC also, but it will "latch-on", and the Anode/Cathode
current flow will
need to be interrupted to shut it off again.
You will need to apply a "snubber" circuit across it, (Anode to Cathode) to
prevent false
triggering when you first power up.
If you're intending this for AC control, you might check out a device called a
Triac.
This is essentially two SCR's "Back-to-Back" to provide full wave power to your
load.
Again, this device needs snubbing also, to prevent false triggering.
Sorry for the length.
Russ
Original Message
From: "Don" <renegade.engineer@v...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, June 17, 2002 8:51 PM
Subject: Re: [noparse][[/noparse]basicstamps] Stamp Outputs
SCR's? Help on the acronym please.
Don
Original Message
From: "jrem123" <jrem123@y...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, June 17, 2002 2:01 PM
Subject: [noparse][[/noparse]basicstamps] Stamp Outputs
> Hi: Maybe this has been answered before but a little digging around
> didn't uncover it . . . I see the output pins are 20 ma each
> sourcing, 50ma total on a bank, 50ma total with the internal voltage
> supply. So if I want to drive a few of those nifty SCR's that
> requires 15ma I might run out of current real quick. So I'm thinking
> of putting a 2N2222 npn device between them. Is that the way to go
> or is there another solution for this?
>
> Thanks . . . John.
>
>
> 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/
>
>
>
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http://www.amymca.com/optotriac.pdf
http://www.amymca.com/optoG4.pdf
Are these the type of devices normally used on the output pins of a
stamp module? Thanks . . .