ULN2003, zener diode and a stepper motor

[dusko]

I am trying to build a stepper motor (from an old floppy drive), using a PC parallel port and ULN2803. To protect the IC, a zener diode is recommended. On some sites I see that the diode's anode is connected to +12V:

**broken link removed**

while on some others, anode goes to pin 10 of ULN2803:

**broken link removed**

Could you please clarify?

Thanks,

Dusko

 

[ClydeCrashKop]

Search this forum for snubbing diodes on A B C & D that direct negative voltages to ground. Forget the zener.

 

[Gayan Soyza]

ZENNER diodes ANODE must connect to the GND that is 9th pin in ULN 2803A.
& the ZENNER diodes CATHODE must connect to + VDD.

The back EMF protective diodes are inbuilt with it. To make active the back EMF protective diodes pin 10 must give to the VDD.