Basic Electrical Concepts Current is the flow of electrical
energy. It flows through a wire similar to the way water flows
through a hose. A small stream of water can flow easily through
a small hose, while larger flows require larger hoses. The same
is true for electrical current. A small amount of current can be
carried by a thin wire, but a large amount of current requires
heavier wire. Current is measured in amperes, often called amps.
Voltage is electrical pressure that causes current to flow.
Voltage is measured in units called volts. Voltage pushes
current through a wire the same way pressure pushes water
through a hose. A wire connected to a voltage source is said to
be energized or hot. However, there must be enough voltage to
overcome the wire’s electrical resistance before current will
flow. Resistance is the opposition that a material presents to
the flow of current. It is measured in units called ohms.
Current can be passed easily through some materials. Copper
wire, for example, has low electric