I’m planning to use the same H-bridge for a robot (my 1st robot and 1st H-bridge), so I’m very greatful for this istructable. Thanks
But excuse me for asking a noob question: Are ALL those capacitors (9?) really necesary just to control to DC motors? Or is it because you’re using UNREGULATED power? Or some other specific circumstances?
required? No. suggested? required? No. suggested? yes! They suppress noise and help with the discharge when the magnetic field collapses after the motors are shut off. (Note: In not an EE major so someone may prove me wrong but that is my understanding.)
Well… I was planning to use a cap or two. However 7 seems like a bit of a hassle, so I think I’ll try it with less for starters and see how that goes. Did you start with 7 or is it because you had problems when using less?
I started with just the L293D, the motors and the microcontroller, and it works ok
I used the caps because they were on the schematic and I wanted to learn how to use them on the h-bridge. I is just a matter of getting used to, now, I can’t think in making this circuit without the caps.
Hmmm…error in the diagram? It seems that the small caps (0.1uF) are depicted with the symbol for electrolytic caps, but they sure look like ceramic caps on the fotos? Correct me if I’m wrong?..
Damnit I think you’re right. The 3rd kind I allways forget. Another noob mistake on my part. Man it isn’t easy learning electronics. A lot of incomplete or wrong information around. Guess I’ll have to find a better symbol list.
Besides these things look VERY similar to the ceramic ones
No plus sign = ceramics probably. Note the plus on the actual electrolytic. Sometimes folks use whatever symbol is handy (in graphics) for the device they have.
It does appear they have a place for caps on the LadyAda Motorshield between ground and motor outputs, but they appear to not be populated. I’d probably omit those 4 too.
I’ll keep that in mind And the problem with the symbols is that the description I posted above (as well as many others) says the symbol with a plus sign is an ELECTROLYTIC cap. That’s apparently incorrect. It simply means a POLARIZED cap? Furthermore the ones with no plus could mean both a tantalum or ceramic one, allthough tantalum caps are polarized too? Oh well I’ll get used to it sooner or later…
HOW can you tell it’s a tantalum cap judging from the appearance, value and polarisation?
According to the diagram they’re NOT polarized (tantalums are). The value could be both ceramic and tantalum (or am I wrong?). And the appearences of the two types are extremely similar…
There are other There are other non-polarised types too, such as polyester, aluminium foil, green caps… At the end of the day only a few things really matter for most uses: capacitance, maximum voltage and polarity. Sometimes you’ll need to know the equivalent series resistance, leakage rate, or other details but normally you don’t worry about them.