help required in driving Bipolar stepper using uC in Proteus simulator,

you provided a scematic of NPN's, but do i always have to use in Darlington form,
can i not use as single form, not in darlington configuration??

---------- Post added at 14:13 ---------- Previous post was at 14:09 ----------

and next
i got a L298n IC,
now any suggestions, from where should i start??
i have read briefly its data sheet, but still of no use....... and now i have started gooogling l298 circuits

yes. but darlington provides move power to the motor

---------- Post added at 14:54 ---------- Previous post was at 14:53 ----------

read the datasheet but focus of the application section, most of the datasheet has this but some unfortunately not

The Darlington configuration is when the emitter of the first transistor drives the base of the second transistor , like the picture below, my configuration is not Darlington.
In every transistor the emitter has a voltage difference of about 0.7V with the base , since we are driving with 5v the output at the emitter of the upper transistor of the half bridge would be 4.3v so i use the driving transistor to feed the base with 0 or 12V so that the output is 11.3V.
When the driving NPN is not conducting the 500 ohm resistor is working as a pull up resistor and gives 12v to the base, when the driving NPN is on then the current flows through the resistor and the voltage drop creates a voltage of almost 0.
If you are using a 5v power supply then you can drive the upper transistor without the driver.

Alex