
Originally Posted by
Christopher4187
However, it appears I am using the incorrect ULN model. If pin 9 needs to be connected to V+, I need the CMOS version. The relay I am using is a 12 volt version.
You dont need to change at all.
Pin 9 is the pin which all the clamping diodes are connected. This should be connected to the supply voltage of the relays/lamps that you are driving. Irrespective of which chip you are using this can be upto 50V.
The TTL/CMOS versions feature different inputs for driving from those logic families. The PIC can drive either type. The supply voltage for the relays/lamps has no bearing on which input type you need.
Just make sure that you dont accidently connect your load supply to your logic supply or the magic smoke will escape
Keith
www.diyha.co.uk
www.kat5.tv
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