Download current electricity

CURRENT ELECTRICITY
A current is the flow of charge.
In metals, electrons flow toward the positive
terminal of a cell.
-
+
CURRENT ELECTRICITY
The faster the charges flow, the
greater the current.
-
+
CIRCUITS
What makes a current flow?
A POTENTIAL DIFFERENCE (VOLTAGE)
How is the current affected by increasing
the voltage?
The charges will flow faster, so the current will
increase.
If the resistance is increased, what will
happen?
The charges will flow slower, so the current will
decrease.
+
The cell gives electrical
energy to the electrons
The electrons
use their
energy to do
work in the
bulb
The
electrons
return to
the cell
and get
more
energy
1. How would the readings on the ammeter and the
voltmeter be affected if a second resistor, identical to
the first was added in series.
12V
The current will be affected by
the total resistance in the
circuit. If the resistance is 2A A
doubled, the electrons will
move twice as slowly so the
new current reading will be 1A
V
If the charges are flowing
slower less work will be done
12V
as they move through each resistor,
the voltage provided by the cell will be shared. The
reading on the voltmeter will drop to 6V.
2. How would the readings on the ammeter (initially 2A)
and the voltmeter (initially 12V) be affected if a second
resistor, identical to the first was added in parallel?
12V
Every electron will have
12V to use to do work, but
it has a choice of two paths
A
V
to take. The voltmeter
reading will still read 12V.
The voltage across the
second branch of this
parallel circuit will also be
12V. The cell in this circuit will run down faster than one
attached to a series circuit. It is, essentially, being used by
two circuits at the same time. The current drawn will be
twice as large. The ammeter will read 4A. This will split up
and 2A will then flow through each branch.