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Topic: L293D or SN754410 - any difference between these two besides max current? (Read 1 time) previous topic - next topic

garthn

I've tried the circuit from this website for driving a bipolar stepper - it worked but I subsequently nuked two Unos and two SN754410s playing with the wiring.  I'm now trying a third Uno (getting pretty expensive now) - and as I could not get SNs locally I bought L293Ds instead.

Can I simply wire the Uno to the L293D and then to the motor? or do I need additional circuitry? This website shows just a Uno and SN with no other circuitry - but lots of other sites show more components.

The stepper is a small motor out of an Epson printer

MarkT

They are similar...  If you put series resistors between Arduino pin and motor driver inputs then its safe to have motor driver powered down when Arduino still running. 4k7 or such may be a good value.  Decoupling capacitors are never optional for logic-speed switching, note, so the motor driver chips should have decoupling caps.  If the bridge IC lacks flyback diodes they will be needed, check datasheet.
[ I won't respond to messages, use the forum please ]

gazz

Eeeek, tell me more about the protection needed when playing with these H-bridges please.

i've got one on order, plan to use it with an air-core gauge to start with, so very low current, but i also have a stepper motor from an epson printer i want to play with, and last thing i want to do is nuke my mega.

i'm new to most of this, so diagrams would be great.

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