3. Voltage: V (volts)
• Measure of the “electric potential” or “potential
difference”
• How much “ummmph” electricity has
• It is how much “push” there is behind the
electrons
• A 12 volt battery has more push than a 1.5 volt
battery.
• Car analogy: Horsepower of the engine
• Water analogy: Pressure in the hose
4. Current: I (Amps)
• Measure of electrical flow
• # of electrons per unit of time
• Car analogy= Amount of cars (traffic
flow)
• Water Analogy= Amount of water
5. Resistance: R (Ohms)
• “It’s like electrical
friction”(Luis P)
• It is the sum of forces that slow
down the electric flow
• Electrons have to push their
way around the atoms in the wire
• Car analogy: Road conditions
and number of lanes
6. Resistance
• Affected by:
– Thickness of wiring or circuit parts
– Material of wiring or circuit
– Length of wiring or circuit
– Temperature
– Amount of paths available
8. Consider the equation…
• If you increase the resistance, then the
voltage must increase in order to have the
same current. (If it’s harder to get through
something, then you need more push in
order to stay at same speed.)
• Increasing the current will increase the
voltage if resistance stays the same (more
electrons have more push)
9. Misconceptions
• Electrons in wires move near the speed of
light (T/F?)
– False: They move like a train.
• When batteries die, they have run out of
electrons (T/F?)
False: Batteries have completed their chemical
reactions when they “die”
10. More misconceptions
• Batteries produce electrons. (T/F?)
– False: Batteries give electrons a push--an
energy boost—an increase in voltage.
• Less electrons come out of a light bulb than
those that went in. The filament uses them
up.(T/F?)
– False: The electrons simply lose voltage as
electrical energy gets converted to light and
heat
