1. 16.2 Current and Voltage

2. Electric Current (review from yesterday)
Electric current: the flow of electric charge (movement of electrons)

3. Current Electric current carries energy in a circuit.
Current is measured in amperes (A)
amount of current entering a circuit = amount of current exiting

4. To measure current you must force the current through a multimeter
Measuring Current
To measure current you must force the current through a multimeter
multimeter
A multimeter can measure alternating current (AC) or direct current (DC)
- use DC with batteries and light bulbs

5. Voltage Voltage: a measure of electric potential energy
Voltage is measured in volts (V)
1 volt = 1 amp of current does 1 J of work in 1 second
Static electricity: less than one millionth of a coulomb
A difference in voltage provides the energy that causes current to flow.

6. Measuring Voltage
To measure voltage touch a multimeter’s probes to two places in a circuit or across a battery.

7. Batteries
A battery uses stored chemical energy to create the voltage difference.
Two chemicals react inside the battery cell and release the energy that pushes charges around the circuit. The reaction is ‘rolling down’ the energy hill when energy is released from the cell. The equation for the reaction is:
A + B  C + D + energy

8. What is the total voltage in this flashlight?
Batteries
What is the total voltage in this flashlight?