Open Collector using ULN2003A

Sparks_21 · Feb 18, 2011

Hi guys I wonder if you could help me,

Here is a simple circuit that i am using.

when the Switch is open, i need it to trigger my LCD module Board that requires open collector inputs. - 6 inputs will display 6 different messages when activated.

So here comes the question, if i take the output from this (from zone 2) and feed it into the ULN2003A (Darlington Transistor Array) and then the output from that too the inputs of my LCD module will this trigger it?

I will try to supply as much Information as i can,

Thanks in advance

Marc

(*steve*) · Feb 18, 2011

Firstly, a 4050 does not have an open collector (or open drain) output.

You could put a diode in series with the output, the cathode closest to the 4050's output and you would achieve a similar effect.

Sparks_21 · Feb 18, 2011

Right ok, Thanks for your reply.

(*steve*) · Feb 18, 2011

I misread your question. the ULN2003 or whatever probably has open collector outputs. But I doubt that you need so much power for your application. I would try the diode trick with your buffer first.

Sparks_21 · Feb 21, 2011

I got it working with the ULN2003A

Open Collector using ULN2003A

Sparks_21

Attached Files:

test.jpg

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Open Collector using ULN2003A

Attached Files:

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