Digest Number 37
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Posts: 46,084
> WOW! it works! It CAN work!!
>
> Dwayne - yew da man!
>
> To make it more like the current coming from the basic stamp circuits,
> I then put the 9 volt battery onto the board of education, and jumped
> the 5volt (-) lead to pin 8. Jumped the 5volt (+) from the battery to
> each of the three input pins across from the 14/15/16 pins one at a
> time, causes the corresponding traffic lite to go on!!!! it works
> even at 5 volts!
>
> SOOOO, if I had only had a "right" strength ULN at the gitgo, this
> all would have worked the first time - whoops, except wait a
> minute...
The ULN cannot source current so will not work with your grounded
relays. You could use 3 PNP Darlington transistors(with base
resistors) in which case a low from the STAMP would turn the relay
on.
>
> Dwayne - yew da man!
>
> To make it more like the current coming from the basic stamp circuits,
> I then put the 9 volt battery onto the board of education, and jumped
> the 5volt (-) lead to pin 8. Jumped the 5volt (+) from the battery to
> each of the three input pins across from the 14/15/16 pins one at a
> time, causes the corresponding traffic lite to go on!!!! it works
> even at 5 volts!
>
> SOOOO, if I had only had a "right" strength ULN at the gitgo, this
> all would have worked the first time - whoops, except wait a
> minute...
The ULN cannot source current so will not work with your grounded
relays. You could use 3 PNP Darlington transistors(with base
resistors) in which case a low from the STAMP would turn the relay
on.
Comments
your statement.
Words I don't grok include "source current", PNP, base resistors ,...<G>
It appears to me that I have it the NTE2014(ULN 2003) working as I need it
to although I'm still waiting for UPS to deliver a basic stamp II to me so
that I can do a final assembly and test....also, I thought the ULN WAS a
darlington. Is a "PNP" darlington different from the NTE 2014 that I
have?
Mike DeMetz wrote:
> The ULN cannot source current so will not work with your grounded
> relays. You could use 3 PNP Darlington transistors(with base
> resistors) in which case a low from the STAMP would turn the relay on
--
ARC in Lago Vista, TX
A complex system that does not work is invariably found to have evolved from
a simpler system that worked just fine.
> >
> > SOOOO, if I had only had a "right" strength ULN at the gitgo, this
> > all would have worked the first time - whoops, except wait a
> > minute...
>
>The ULN cannot source current so will not work with your grounded
>relays. You could use 3 PNP Darlington transistors(with base
>resistors) in which case a low from the STAMP would turn the relay
>on.
I think you may have missed most of the thread, Mike. He has a box with
relays inside, already wired to a power supply. What he has coming out of
the box is 4 wires, one of those wires goes to one side of the power
supply, the other 3 going to relay coils. A short between the PSU wire to
a relay wire closes that relay and turns on his light. The power supply
wires going into his box are not polarity sensitive - he can make the power
supply any polarity he wants.
I think his original problem was the lack of back EMF clamps on the relay
coils. I helped him take care of that problem by adding a RC snubber to
the diode clamp pin on the '2003.
dwayne
Dwayne Reid <dwayner@p...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
Celebrating 16 years of Engineering Innovation (1984 - 2000)
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