Let's Make Robots!

Why wasn't my circuit working?

For my second Bot, I had used the following circuit:

This is my final circuit, but before that, I had made the circuit here:

But I wonder why it didnt work, In this circuit, i used two seperate batteries, using -ve of one battery and +ve of the other to complete the circuit... 

But only one motor worked...Can anyone sort out some mistake in this please....because I was confident that this circuit shall work...!



Sorry for any bad english of mine spoken here, I have Indian accent...

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Always when you have more that one (1) battery all the grounds have to be connected.


I guess I've connected both of em' ... for motor 1,Volt from battery 1 to ground of battery 2... and for motor 2, volt from motor 2 and ground to battery 1...


Bcause if there had to be a perpanent error then none of my motors have worked out...but 1 of em' did!

I still can't figure out anything impractical..


I mean that the ground from battery 1 and ground from battery 2 have to be connected to each other, otherwise there is no path for the electrons to go back to the battery where they came from.


now I can understand it truely well!

Thanks a ton!

Glad to have made a new circuit by now!

You are probably making some sort of beetlebot and should have a look at this.



Thanks, but at the moment I'm not making a beetleBot... I've added the link of my second Bot above already, but you can also find it here (I know it's bad looking but it's circuit took me 2 hours to settle in my mind)...

And I've already made it, but I am still curious to know why my first circuit didn't work.!

I can’t see how you circuit would work as your not completed the ‘circuit’. You can’t make a motor run with two batteries if they’re not connected. Current won’t flow from one battery into the other.
You need to connect the batteries either in serial or parallel. If you connect them in serial you have –V in one end +V in the other end and 0V in the middle.