Quick Opto-Coupler Question
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Since on a 6 pin Opto coupler (4N33) the Base is connected to Pin 6. What should I do with it? Leave it not connected or should it be terminated in some way?
Thanks,
Richard
[noparse][[/noparse]Non-text portions of this message have been removed]
Thanks,
Richard
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
<rwskinner@a...> wrote:
>
>
> Since on a 6 pin Opto coupler (4N33) the Base is connected to Pin
6. What should I do with it? Leave it not connected or should it be
terminated in some way?
>
> Thanks,
> Richard
>
Depends on what you want to do.
you can add a switch with this as the open pin and the transistor
will fire from either the opto input or the switch input.
Leave it unconnected if all you want is the opto to fire the
transistor.
Dave
TB - Terminal Blocks When the two terminal blocks are shorted together it
grounds pin 2 of the opto causing it's led to go high. That in turns turns
on the transistor, allowing 5 volts to go into my controllers input, causing
the input to register as high. At the same point, the LED Lights showing
the input at the terminal blocks has been turned on (shorted).
On my controller board, my inputs are already pulled low with a 1 k
resistor, so I doubt I need the 4.7 in there pulling it down.
I inserted a 1k between the controller input pin and the transistor output.
Sorry for the poor drawing, all I had was MS Paint.
Richard
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 16, 2004 4:47 PM
Subject: [noparse][[/noparse]basicstamps] Re: Quick Opto-Coupler Question
> --- In basicstamps@yahoogroups.com, "Richard Skinner"
> <rwskinner@a...> wrote:
> >
> >
> > Since on a 6 pin Opto coupler (4N33) the Base is connected to Pin
> 6. What should I do with it? Leave it not connected or should it be
> terminated in some way?
> >
> > Thanks,
> > Richard
> >
>
> Depends on what you want to do.
>
> you can add a switch with this as the open pin and the transistor
> will fire from either the opto input or the switch input.
>
> Leave it unconnected if all you want is the opto to fire the
> transistor.
>
> Dave
>
>
>
>
>
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Original Message
From: "Richard Skinner" <rwskinner@a...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 16, 2004 5:05 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Quick Opto-Coupler Question
> Could you look this over before I etch a board and see if it looks okay.
> TB - Terminal Blocks When the two terminal blocks are shorted together it
> grounds pin 2 of the opto causing it's led to go high. That in turns
turns
> on the transistor, allowing 5 volts to go into my controllers input,
causing
> the input to register as high. At the same point, the LED Lights showing
> the input at the terminal blocks has been turned on (shorted).
>
> On my controller board, my inputs are already pulled low with a 1 k
> resistor, so I doubt I need the 4.7 in there pulling it down.
>
> I inserted a 1k between the controller input pin and the transistor
output.
>
> Sorry for the poor drawing, all I had was MS Paint.
>
> Richard
>
>
>
>
>
>
Original Message
> From: "Dave Mucha" <davemucha@j...>
> To: <basicstamps@yahoogroups.com>
> Sent: Wednesday, June 16, 2004 4:47 PM
> Subject: [noparse][[/noparse]basicstamps] Re: Quick Opto-Coupler Question
>
>
> > --- In basicstamps@yahoogroups.com, "Richard Skinner"
> > <rwskinner@a...> wrote:
> > >
> > >
> > > Since on a 6 pin Opto coupler (4N33) the Base is connected to Pin
> > 6. What should I do with it? Leave it not connected or should it be
> > terminated in some way?
> > >
> > > Thanks,
> > > Richard
> > >
> >
> > Depends on what you want to do.
> >
> > you can add a switch with this as the open pin and the transistor
> > will fire from either the opto input or the switch input.
> >
> > Leave it unconnected if all you want is the opto to fire the
> > transistor.
> >
> > Dave
> >
> >
> >
> >
> >
> > 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
> >
> >
> >
> >
> >
> >
> > [noparse][[/noparse]Scanned by AwesomeNet Anti-Virus]
> >
> >
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> Sorry, the schematic I attached did not stay with it.
>
Hello Richard.
Attachments are not allowed on the basicstamps forum.
If you have a file that you want to share with other members, you
have to upload it in the files area:
http://groups.yahoo.com/group/basicstamps/files/
Saludos,
Aristides Alvarez
Education Manager
aalvarez@p...
Parallax, Inc. www.parallax.com
California, USA
I don't see any significant problem with the circuit the way described.
I do have a question though. There are two pull down resistors shown on pin
4, 1k, 4.7k.
Why are there two pull downs?
And also, with your latest configuration, there are three resistances in
parallel from pin 4 to ground. 4.7k, 1k, and the resistance of the LED & 470 ohm
leg of the circuit. The total current the transistor portion needs to source
is about 14 mA, which should not be a problem.
Although this looks harmless on paper, I would recommend you breadboard the
circuit and be sure it works as expected before having a pcb made.
ken
I revised it some: I didn't like the way the LED Indicator was so I
Grounded the LED then went from the LED thru a 470 ohm resistor to Pin 4 of
the opto. That way when the opto goes high it lights the LED.
[noparse][[/noparse]Non-text portions of this message have been removed]
Questions:
Operation: Short the two terminals on TB1 together makes Opto LED light.
This in turn turns on the transistor allowing 5 volts to flow to the
controllers input pin. It also Lights the Indicator LED.
Am I screwing up wiring my LED the way I am? I'm hooking in up upstream of
the opto.
Does the schematic in general appear okay?
My parts won't be in until Friday but I wanted to etch the board tomorrow.
So I needed the opinions of experts.
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 16, 2004 4:47 PM
Subject: [noparse][[/noparse]basicstamps] Re: Quick Opto-Coupler Question
> --- In basicstamps@yahoogroups.com, "Richard Skinner"
> <rwskinner@a...> wrote:
> >
> >
> > Since on a 6 pin Opto coupler (4N33) the Base is connected to Pin
> 6. What should I do with it? Leave it not connected or should it be
> terminated in some way?
> >
> > Thanks,
> > Richard
> >
>
> Depends on what you want to do.
>
> you can add a switch with this as the open pin and the transistor
> will fire from either the opto input or the switch input.
>
> Leave it unconnected if all you want is the opto to fire the
> transistor.
>
> Dave
>
>
>
>
>
> 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
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>
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> [noparse][[/noparse]Scanned by AwesomeNet Anti-Virus]
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>
Grounded the LED then went from the LED thru a 470 ohm resistor to Pin 4 of
the opto. That way when the opto goes high it lights the LED.
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 16, 2004 4:47 PM
Subject: [noparse][[/noparse]basicstamps] Re: Quick Opto-Coupler Question
> --- In basicstamps@yahoogroups.com, "Richard Skinner"
> <rwskinner@a...> wrote:
> >
> >
> > Since on a 6 pin Opto coupler (4N33) the Base is connected to Pin
> 6. What should I do with it? Leave it not connected or should it be
> terminated in some way?
> >
> > Thanks,
> > Richard
> >
>
> Depends on what you want to do.
>
> you can add a switch with this as the open pin and the transistor
> will fire from either the opto input or the switch input.
>
> Leave it unconnected if all you want is the opto to fire the
> transistor.
>
> Dave
>
>
>
>
>
> 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
>
>
>
>
>
>
> [noparse][[/noparse]Scanned by AwesomeNet Anti-Virus]
>
>
carrier board already had 1k resistors from the input pins pulled to ground.
I just put the spot there for pull downs if needed in the future for some
reason.
The 1K from pin 4 was in series with the controllers input pin for standard
pin protection which probably isn't needed for an input, but for some
reason, if the input on the the controller is configured as an output and is
low then the 1 k prevents a dead short? Basically, most of the schematics I
looked at seems to always have 1k resistors between the controller pins and
the other chips. If it doesn't get messed up, the ascii art below shows
how the resistors really are arranged. There isn't two in series pulling to
ground.
1k wwwwww
Controller Input
opto |
#4
--|
|
4.7k wwwwww
Ground
I moved the Indicator LED's off the upstream side of the opto, because I
though there was a chance they may case a problem but honestly, I didn't see
how. I preferred them off the 24 volt side where I have a larger power
supply but moved them to the output of the opto to be safe.
As far as the 3 resistors and LED being off the output of the transistor, I
didn't think it would hurt anything seeing the 4n33 is a photo Darlington
with a dual transistor output. I have to look, but I think it was rated up
to 150 ma.
Well, what makes sense to me surely may not be the correct way. That is
pretty much why I'm asking for advice/opinions so I can learn why or why not
to do something.
Original Message
From: <smartdim@a...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 16, 2004 10:50 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Quick Opto-Coupler Question
>
> Hello,
>
> I don't see any significant problem with the circuit the way described.
>
> I do have a question though. There are two pull down resistors shown on
pin
> 4, 1k, 4.7k.
>
> Why are there two pull downs?
>
> And also, with your latest configuration, there are three resistances in
> parallel from pin 4 to ground. 4.7k, 1k, and the resistance of the LED &
470 ohm
> leg of the circuit. The total current the transistor portion needs to
source
> is about 14 mA, which should not be a problem.
>
> Although this looks harmless on paper, I would recommend you breadboard
the
> circuit and be sure it works as expected before having a pcb made.
>
> ken
>
> I revised it some: I didn't like the way the LED Indicator was so I
> Grounded the LED then went from the LED thru a 470 ohm resistor to Pin 4
of
> the opto. That way when the opto goes high it lights the LED.
>
>
>
>
>
> [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.
>
> Yahoo! Groups Links
>
>
>
>
>
>
> [noparse][[/noparse]Scanned by AwesomeNet Anti-Virus]
>
>
<rwskinner@a...> wrote:
> I revised it some: I didn't like the way the LED Indicator was so I
> Grounded the LED then went from the LED thru a 470 ohm resistor to
Pin 4 of
> the opto. That way when the opto goes high it lights the LED.
>
>
.
.
I'm not sure why you are using an isolator ?
you have the two circuits connected together.
Why not eleminate it and just use a voltage divider
with a 10k ohm to the Stamp input ?
If you need more power, or want the LED on the Stamp side, you can
substitute a npn transistor.
If you want isolation, disconnect the common ground line and the
resistor in it. If you can share the common ground, then the
circuits are not isolated and you don't need the isolator.
Dave
Reason for using the Opto, because I wanted to be safe in using the 24
volts. I also looked at the Stamp PLC and it had a very simular circuit so
I thought it was the way to go.
I guess there is a dozen ways to skin a cat.
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, June 17, 2004 10:17 AM
Subject: [noparse][[/noparse]basicstamps] Re: Quick Opto-Coupler Question
> --- In basicstamps@yahoogroups.com, "Richard Skinner"
> <rwskinner@a...> wrote:
> > I revised it some: I didn't like the way the LED Indicator was so I
> > Grounded the LED then went from the LED thru a 470 ohm resistor to
> Pin 4 of
> > the opto. That way when the opto goes high it lights the LED.
> >
> >
>
> .
> .
> I'm not sure why you are using an isolator ?
>
> you have the two circuits connected together.
> Why not eleminate it and just use a voltage divider
> with a 10k ohm to the Stamp input ?
>
> If you need more power, or want the LED on the Stamp side, you can
> substitute a npn transistor.
>
> If you want isolation, disconnect the common ground line and the
> resistor in it. If you can share the common ground, then the
> circuits are not isolated and you don't need the isolator.
>
> Dave
>
>
>
>
>
> 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
>
>
>
>
>
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