11.3 Measuring the Properties of a
Simple Circuit
Learning Goals
• Learn how to draw circuit diagrams
• Learn how to measure currents and potential
differences
Summary
Circuit Diagram
• A circuit diagram is a diagram
that uses standard symbols to
represent the components in an
electric circuit and their
connections.
Drawing Circuit Diagrams
• There are some conventions (rules) to follow when drawing
circuit diagrams:
• connecting wires are generally shown as straight lines or
90° angles
• Symbols are used to represent all components such as
control devices, outlets, electrical loads, meters
Symbols
Examples of Circuits
Series Circuit
Series circuit a circuit in which there is only one path
along which electrons can flow
Parallel Circuit
Parallel circuit a circuit in which there is more than one
path along which electrons can flow
Measuring Current
Ammeters are devices used to measure the electric current
(amperes) in a circuit.
• Ammeters are always connected in series within a
circuit in order to measure the current flowing through
a resistor.
What is electric current?
Measuring Potential Difference
Voltmeters are devices used to measure potential difference
(voltage) between two points in a circuit.
• Voltmeters are always connected in parallel to measure
the voltage change across a component in a circuit.
What is potential difference?
Multimeters
A multimeter is a device that can be set as either an
ammeter to read the current or a voltmeter to read the
potential difference.
Increasing Potential Energy
The potential difference across a battery of cells in series is
the sum of the potential differences across each cell.
Potential Difference Analogy
Adding cells in series to a battery is like raising the gravitational
potential of a box by lifting it to a higher shelf.
Increasing
potential
energy
http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc