Arduino circuit not working with normal power supplies; only batteries

Using Arduino Motors, Mechanics, Power and CNC
1

Hi there, would appreciate any help;

Basically circuit consisting of an Arduino Uno, 2 Pololu stepper motor drivers and 2 stepper motors will only power up when I use a 9v battery. It wont power up when using a 9v power supply. Could someone link me a power supply that would work or at least suggest why it is not working.

Thanks
Jack

2

Because you haven't connected the grounds together?
Because the supply isn't connected to the mains?
Because the supply can provide even less current than the battery?
Because the supply is broken?

3

I think its most likely because the power supply is limited to 1A, could that be it?

4

Jackdowniels:
I think its most likely because the power supply is limited to 1A, could that be it?

Very likely.

Lefty

5

Long, skinny power leads can be a problem. Too much inductance can slow the voltage rise time down to a point that some parts won't come out of reset properly or at all. Try bringing your power leads over to a spot on the breadboard and put an electrolytic cap across it. Then make and break your power connection from there and see if it makes any difference. It's something to try.