1. Current, Resistivity, Semiconductors

2. Current The movement of charge Symbol is I, unit is A amp
I=q/t Amp= coulomb/sec
Conventional Current from positive to negative

3. Battery Batteries produce direct current
The difference in electrical potential energy is called electromotive force emf
Work done by a battery= amount of charge X emf of battery
W=∆Qε

4. Resistance
Collisions between electrons and atoms in a wire cause resistance creating an opposition to the flow of charge
Symbol is R, unit is Ohms Ω
R= V/I

5. Ohm’s Law
V= I/R V I R

6. Resistance Wire’s resistance is affect by 1. Type of material
2. Length
3. Temperature
R=ρ(L/A)

7. Semiconductors Go to page 754-756
Outline the types of semiconductors and their behaviors,
Define diodes and explain how they work,
Describe how transistors work and why they are important
Work Lesson Check p ,12-14