Stepper Motor Driver Schematic
Uln2803 Stepper Motor Driver

Hello!
I have problem with my stepper motor and ULN2803.
I interfaced Bipolar stepper motor through ULN2803 to PIC18F4550, I made code to run motor Clock wise It works on Simulation but not on Hardware!
Im using 12V 4 wire bipolar motor .
Im using this circuit .
Also I tested Unipolar motor on same hardware!! didnt work!!.
when I checked voltage using DMM at pin num 9 and 10 of ULN2803 I get 12V but when I checked voltage at output pins I get 2.3-2.5V and when I run sequence the voltage at output pin changes like 0 to 2.5v to 0v until sequence ends!! But my stepper motor doesn't rotate.. Why and how this is happning what is the problem Help me!!
Thanks!!!

Stepper Motor Driver Schematic

Uln2803 Stepper Motor Driver

Unipolar stepper motor drives, bipolar stepper motor drive circuits, control and power supply cards that will benefit CNC Projects. High power designs as. 8-lead relay with 10 amperes relay with ULN2803 driver isolated with PC817 Opto koubler for use with LPT port or microcontroller. Circuit Boards And Parts. The following picture is of an assembled circuitboard for the Unipolar Stepper Motor Driver. The board measures 1.9 inches by 2.9 inches and has been commercially made.

Uln2803 Stepper Motor Driver Circuit