1. 9.1 Series and Parallel Circuits BC Science 9: p. 306-319

2. Voltage and Current in Circuits The voltage in a circuit must always be consumed before returning to the source. The sum of the voltage lost on the loads of the circuit will equal the total voltage of the source. The current in a circuit must always be accounted for and will never disappear or be consumed. – Current in a circuit is similar to water flowing through pipes.

3. Series Circuits There is only one path for current to travel. Since there is only one path for the electrons in a series circuit, the current in each part is equal. Current must pass through all loads in the circuit.

4. Series Circuits The voltage is shared by all loads in the circuit and be used up before returning to the source. Each load in a series circuit uses a portion of the total voltage. When a load or resistor is added in series, the overall resistance of the circuit increases.

5. Parallel Circuits There are multiple paths for current to travel. Current will split as some electrons go each way. When the pathways re-join, so does the current. The sum of the current in the pathways must equal the overall current in the circuit.

6. Parallel Circuits When the electrons cycle through the circuit they must choose only one path. The voltage drop at each load is equal to the voltage supplied by the source. When a load or resistor is added in parallel, the overall resistance of the circuit decreases.