ULN2003, zener diode and a stepper motor - Electronic Circuits Projects Diagrams Free

dusko · 6th August 2007, 11:08 PM

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:

http://www.doc.ic.ac.uk/~ih/doc/step...2/connect.html

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

http://http://www.epanorama.net/circ...put.html#input

Could you please clarify?

Thanks,

Dusko

ClydeCrashKop · 7th August 2007, 01:36 AM

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

Gayan Soyza · 7th August 2007, 05:46 AM

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.

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6th August 2007, 11:08 PM	(permalink)
dusko	ULN2003, zener diode and a stepper motor 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: http://www.doc.ic.ac.uk/~ih/doc/step...2/connect.html while on some others, anode goes to pin 10 of ULN2803: http://http://www.epanorama.net/circ...put.html#input Could you please clarify? Thanks, Dusko

7th August 2007, 01:36 AM	(permalink)
ClydeCrashKop	Search this forum for snubbing diodes on A B C & D that direct negative voltages to ground. Forget the zener. __________________ C:\WHUT ? Beware the asterisk *

7th August 2007, 05:46 AM	(permalink)
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. __________________ Gayan My Website http://gsmicro.blogspot.com/