11.3 MEASURING THE PROPERTIES OF SIMPLE CIRCUITS

Circuit diagrams:

- use standard symbols to represent the components in an electric

circuit and their connections.

The conducting wire is shown as straight lines that connect to form a

rectangle or square.

Series circuits: only one path along which electrons can flow.

Parallel circuits: more than one path along which electrons can flow.

Electric current

- unit: amps (A) or milliamps (mA)

- device to measure:

ammeter or milliammeter (or galvanometer)

Ammeters are always connected in series

A multimeter, when set as an ammeter, measures the

current

Potential Difference (voltage)

- unit: volts (V)

- device to measure: voltmeter

Voltmeters are always connected in parallel

A multimeter, when set as an voltmeter, measures the

potential difference

Cells connected in series (positive to negative, and negative to positive)

Total voltage:

sum of the voltage across each cell

Total voltage:

Voltage across one cell.

Cells connected in parallel (positive to positive, and negative to negative)

What advantages or disadvantages might there be to connecting cells

in either of the two ways?

Adding cells in series to a battery is

like raising the gravitational potential

of a box by lifting it to a higher shelf.

Many familiar batteries contain

several cells that have been

connected in series.