Let's Make Robots!

BEAM turny thingy

turns occasionally

I'm still playing as I learn the basics. The great news is that I have passed on my interest to a third grade student! He is now pestering his mom for permission to tear down unwanted electronics looking for parts. (Don't worry, his family is making sure he doesn't kill himself.)

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Regarding your statement about the resistance on capacitors (aka the ESR), you'll find those that are longer than they are wide tend to have low ESRs and vice versa. It's a physical characteristic of electrolytic capacitors. Both your caps appear to be of the correct design.

It looks like you have them hooked up in parallel, increasing your overall capacitance. This lets you deliver more juice to your motor. Think of it as having a bigger balloon to hold more electron "air." This will in turn "blow" longer on your motor, letting it spin more. What are those caps rated for? I'm inclined to think the big one can handle more farads but maybe it's meant to handle more voltage. Who came first; the big guy or the little guy?

Either way, the large capacitor makes a nice, stable base for new discoveries :)

Hi, thanks for your helping me organize my thoughts on capacitors.   The little one is rated 10uF 63v, the bigger is 4700uF 16v.

I had the big one hooked up and not working, then I added the little one in parallel and it worked well enough for even low lamp light which triggers every 4 minutes or so.  Perfect cat annoying timing :-) 

So I could hook up a gazillion tiny caps in parallel and get the same results?


Also, putting resistances (i.e., the internal capacitor resistances) in parallel reduces the total resistance.

If one of the resistances is much smaller than the other resistance, the total resistance will be, approximately, the smaller resistance.

So, if the big cap had an internal resistance of 30 ohm, and the smaller cap had an internal resistance of 1 ohm, the total resistance would be approx 0.97 ohms.

I don't know if you have seen this, but it has some general info that may help:


Anyway, keep it up, Emma. I like your whimsical aesthetics. Good job on the brainwashing, too!





Thanks!  That is the article I was vaguely remembering .... "You can, of course, also put a small-but-efficient capacitor (namely, a filter cap -- maybe 4.7 uF) in parallel to your storage cap in order to reduce its effective internal resistance"

I can re-read it now with more of an idea what is going on.  

And I think, based on your profile picture, that whimsical isn't a foreign concept in your house either :-)



cool, its just like a symet!