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ULN2803 Problem in active low logic kinldy solve this

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assadmahmood

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Greetings EveryBody!
I have to ask that how can we make ULN2803 output high if respective input is high? Is there any way?
Secondly If I make common high, then if input of some PIN is high then output of that respective PIN goes LOW and all others remain in high impedence state, I want to eleiminate this high impedence state and I want only high and low logic, how to do that?

Many thanks for your kind consideration!
 

ULN2803 is a low side switch intended to be connected to the ground side of the load, are you sure that what you want is a low side switch with inverted operation rather than a high side switch which is intended to be connected to the high side of the load?

I mean devices like **broken link removed**
 

In simple words, ULN2803 is an inverting open collector driver. You can connect an external inverter to make it non-inverting, but you can't make it drive active high.

Depending on your application, a pull-up resistor might be sufficient to achieve push-pull operation. Otherwise I suggest to design a suitable driver circuit on the transistor level.
 

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