1. Series and Parallel Circuits

2. What is a Circuit?

3. Series Circuits In Series – When there is only a single path for the electrons to follow, the circuit is a series circuit –The sum of the voltage drops equals the voltage rise of the source. –The current is the same everywhere in the series circuit. –The total resistance of the circuit is equal to the sum of all of the individual resistances in the circuit.

4. Series Circuit

5. Parallel Circuits In Parallel – When there is more than one path for the electrons to follow, the circuit is a parallel circuit –The voltage drop of each branch equals the voltage of the source. –The total current is equal to the sum of the currents in the branches. –The inverse of the total resistance of the circuit is equal to the sum of the inverses of the individual resistances.

6. Parallel Circuits

7. One important thing to notice –the more branches you add to a parallel circuit (the more things you plug in) the lower the total resistance becomes. –Remember that as the total resistance decreases, the total current increases. –So, the more things you plug in, the more current has to flow through the wiring in the wall. –That's why plugging too many things in to one electrical outlet can create a real fire hazard

8. Ammeter An ammeter measures the current through a resistor –It is wired in series with the resistor that it is measuring the current through –Ammeters have very little resistance An ideal ammeter has zero resistance

9. Voltmeter Voltmeters measure the potential difference across ends of the resistor –Voltmeters are wired in parallel with the resistor over which they are measuring potential difference An ideal voltmeter has infinite resistance

10. Let’s Draw Some Circuits! Proper circuit diagramming symbols Practice drawing series/parallel