Meeting Up with Resistance
In This Chapter
Using resistance to your advantage
Creating just the right amount of resistance with fixed and variable resistors
Understanding how current, voltage, and resistance are governed by Ohm’s Law
Practicing Ohm’s Law by analyzing circuits
Using power as your guide in choosing circuit components
If you toss a marble into a sandbox, the marble won’t go very far. But if you toss a marble onto the surface of a large frozen lake, the marble will enjoy a nice little ride before it eventually comes to a stop. A mechanical force called friction stops that marble on either surface — it’s just that the sand provides more friction than the ice.
Resistance in electronics is a lot like friction in mechanical systems: It puts the brakes on electrons (those teeny-tiny moving particles that make up electric current) as they move through materials.
This chapter looks at exactly what resistance is, where you can find resistance (everywhere), and how you ...