Let's Make Robots!

amp

20Amp Motor Driver/Controller

I am looking for a 20 amp motor controller/driver. I prefer an IC, that way I can integrate my own driver circuitry, but if it is cheap (under 50) post it. I'd prefer if it could provide 20 amps per channel. It will be operating on 12VDC.

Common Electronics Knowledge Questions

Hi LMR. I have already made a robot, as you may know, but all I did (on the physical/electrical side of things) was plug a few cables into the pre-made servo ports on the Board of Education, as my copy of Electronics for Dummies told me to do. I read the entire thing, but they explained a few things in a way I didn't understand. Like the names for stuff, and what each means. Until now, I thought voltage was a measure of battery capacity. I FAIL, I know. I've sorted it out, so now I know about amps and volts, but I have a couple technical questions regarding electricity.

Boosting speakers

Once again, I beseech the robot gods for some info ...

Speakers: How can I boost the sound/tune command from a picaxe to a speaker?

I've got a small 8ohm speaker that I've used in the past, and it works great (as long as the motors aren't droping the voltage) but  I want to boost my output. I've also got a much bigger 1 watt speaker I want to use. How would I boost it?

How to measure Amp?

Could somebody explain in a very easy way (with a drawing of what goes to what) show how one measures how many amp a motor is taking?

Thanks!