Choose a supply that can provide enough current for the motor + PIC +
associated circuitry.  A bigger supply will not harm your PIC as long as
the voltage is regulated.

Whether a motor powered by the 5V supply will affect the PIC depends
on how big your power supply filter caps are and on whether the supply
is big enough to keep the voltage up under load.  Bigger is better, within
reason.  Also, the PIC will be less likely to be affected if it is not in the
current path between the motor and power supply.  That is, it's better if
the PIC (and associated circuitry) and the motor have seperate power
and ground paths (especially ground) back to a common point on the
power supply. If the motor isn't terribly big (and it sounds like it isn't),
then this may not matter, but still it's a good practice when switching
large loads or with circuits that are very sensitive to noise.

> Hello everyone,
>
> I am using a 16F84 to activate a motor that runs off of 5Vdc or 12Vac
> and pulls about 1A.  I am using a 12Vac / 200mA wall transformer for the
> power supply, rectifiying it, and then regulating it at 5V for the PIC.
> (I choose the 200mA supply because of the PIC maximum sinking currents)
> If I use the 12Vac to activate the motor will it still affect the PIC
> even though the power supply would have gone through rectifying and
> regulating before it got to the PIC?
>
> Could I use the 5Vdc instead and just put a diode across the relay I'm
> using to trigger the motor to prevent kickback or would that affect the
> PIC?
>
> My last question is that if the motor requires 1.0A and the wall
> transformer supplies 200mA, will it turn on the motor?
>
> I would appreciate any help.  Thanks in advance.
> Chris Camerlin
>


---
                                        Peace,
                                        William Kitchen
The future is ours to create.