hello guys,

I am using uln2803 for driving my unipolar stepper motor(9v,500mA).

Can one IC driver two stepper motors?

if yes,can anyone provide the circuit?

 

Probably, but what does your current circuit look like?

 

500mA is the specified maximum continuous current for any output.
Maximum power dissipation is 1W for any one channel, and 2.25W for the entire package.

Since your stepper motor requires so much current, you should consider using two channels per motor lead. To spread the heat dissipation across the IC, paired channels should be separate from each other. For example; pair channel 1 with channel 5, channel 2 with 6, etc.

 

so I take it would be impossible to have x8 12v 150mA LED array bulbs connected to a single uln2803 chip (assuming they are strobing very fast, but usually never all on at once)?

 

so I take it would be impossible to have x8 12v 150mA LED array bulbs connected to a single uln2803 chip (assuming they are strobing very fast, but usually never all on at once)?

No, that would be OK - even for continuous duty. With 150mA current, your Vce (saturation voltage) would be around 1 to 1.1v. Each channel would dissipate 1.1v x 0.15A = 165mW, for a total of 1.32W for all eight channels. This is well below the 1W/channel and 2.25W maximum for the package.