Electricity and Electronics Brad Dearing 108 University High School Normal, IL (309)

The Nature of Matter Matter – anything that has mass and takes up space. –Element – the most basic form of a substance.(Sodium) or (Chlorine) Compound – the combination of two or more elements. (Salt) Molecule – the smallest part of a compound that still retains its unique properties. (One small piece of salt) –Atom – smallest part of an element (one sodium atom) Electrons – Negative part of atom (11 electrons in Na) Protons – Positive part of atom (11 protons in Na) Neutrons – No charge or neutral part of atom ( neutrons in Na)

Ionization Ionization occurs when an atom gains or loses an electron. –Positive Ion – more protons than electrons in an atom (loses an electron) –Negative Ion – more electrons than protons in an atom (gains an electron)

Static Electricity Electricity at rest (static) Stationary charge Produced by friction Law of charges: Like charges repel each other and unlike charges attract each other.

Terms Coulomb – the measurement of the amount of electricity. 1 coulomb = 6.24 x electrons Electrostatic Fields – the field of force surrounding a charged body. (dielectric field) See next slide Induction – the transfer of a charge without direct contact, bringing it close to another object.

Basic Electrical Circuit Source of voltage (battery) Load (lamp) Conductors (wires) Polarity

Terms Battery – form of DC electricity, generally by chemical reaction. Load – when electrical energy is converted to some other form of energy. (i.e. light, heat, magnetism, etc.) Conductor – pathway conducive to carrying electricity, generally coated with a protective coating.

Terms Voltage – the force behind electron flow. (volts: V) aka: potential, potential difference, or electromotive force (emf) (E) Current – the flow of electrons. (ampere: A) (I) 1 amp = 1 coulomb of charge flowing past a point in one second. Resistance – the opposition to the flow of electrons. (ohms:  )

Terms Conductor – anything that permits the free flow of electrons. Insulator – extremely poor conductors. Semiconductor – a material that limits the flow of electrons, considered neither a good conductor nor a poor conductor. See table of common conductors and insulators p. 27

Current AC – Alternating Current: flows in both directions. (household current) (Cycle or hertz: Hz) DC – Direct Current: flows in only one direction in a circuit. (battery)

Electron Flow Theory Conventional current flow theory – positive to negative. Electron flow theory – negative to positive.

Series and Parallel

Ohm’s Law E = I x R I = E / R R = E / I voltage current resistance