Chapter 7 – Measuring Electricity. 7.1 – Voltage A battery uses chemical energy to move charges. V olts measure the energy level in a circuit. Adding batteries increases the amount of energy. If a battery has 1.5 V and you use 4 batteries, it is a total of 6 V. Must Draw.
7.1 – Voltage
Electric charge flows from a higher energy (voltage) to a lower energy. The charge flows out the + end of the battery and back to the - terminal of the battery.
Current occurs because the e- in the battery repels the e- in the wire and so on.
If there is no voltage then there is no current.
Current is measured in amperes (amps). 1 amp is the flow of 1 coulomb of charge per second.
In order to measure current you have to make the current flow through the meter.
AC DC Clip
Circuit breakers and fuses are kinds of devices that protect circuits from too much current.
In the US, current alternates 60 times per second but in Europe it reverses 50 times per second.
If you travel to Europe, you need special adapters so that your electrical appliances will not be destroyed.
Conductor is a material that easily carries current. Ex: Metals
An insulator is a material that does not allow current to flow, such as glass or plastic.
Semiconductors are between a conductor and an insulator in the ability to carry currents. Silicon is an example of a semiconductor that is used in computer chips.
Electrical conductivity is the ability of a material to conduct electricity.
High conductivity = good conductor
Low Conductivity = good insulator
High resistance = Difficult for current to flow
Low resistance = Easy for current to flow
Devices that use electricity have resistance. More light bulbs = more resistance = less current
Resistance is measure in ohms ( ). Voltage and resistance determine how much current flows through a circuit.
Physical Science: Elements. Discovery Channel School. 2002.unitedstreaming. 5 December 2007<http://streaming.discoveryeducation.com/>
Parts of a light bulb:
Fluorescent bulbs are more efficient because they do not create as much heat. LED’s produce more light from less electricity than any other type of light source.