Today I demounted some old RC car. And I've got some parts, but I'm fairly new in electronics so I have few questions.
why this engine has stuff on it? http://i.imgur.com/SDQKl4y.jpg
I'm assuming that 1 is capacitor, and 2 is diode. Can't just I desolder it all and just give resistor to the circuit? Or do I have to give an extra capacitor for it? What are the best voltages etc. for this kind of engines?
how to speaker? http://i.imgur.com/HDASjSY.jpg
I've got this speaker, does it work like normal piezo buzzer?
Edit: on the back of speaker there is some info:
F J, 8? , 0.25W/(V?)
That IR (is it IR?) stuff http://i.imgur.com/2mT2RqM.jpg
Can I make something useful from this?
Also there were 3 transistors:
Is there any difference between them? Or stuff that I need to know about them?
Well, sorry for newbies questions.