💡
Electric current
Tags Done
Last edited time @October 1, 2023 9:21 AM
Components and their Characteristics
The diagrams above show some circuit components. Below: is a list of some
notes about them
A cell is a source of electrical energy. Note that a battery is a
combination of cells.
The symbol for an indicator is that same as that for a light source
(including a filament lamp, but not a LED).
A LED emits light when it conducts. However, it only works in one
direction. The direction in which it conducts is called the forwards
direction.
A resistor is a component designed to have a certain resistance.
The resistance of a thermistor decreases as the temperature increases.
This is because it releases electrons and hence, increases the number
of charge carriers in the circuit.
The resistance of a LDR decreases with increasing light intensity.
Electric current 1
, Investigating the characteristics of different components.
To measure the variation of current with potential difference. You can use:
A potential divider to vary the potential difference from zero,
a variable resistor to vary the current to a minimum.
Some notable graphs.
A wire gives a straight line through the origin showing that Ris a
constant value for any current. The resistance can be obtained by
calculating the reciprocal of the gradient. A resistor is also a straight line.
A filament bulb gives a curve with a decreasing gradient because its
resistance increases as it becomes hotter. This is because a higher
current is flowing through the bulb.
A thermistor at constant temperature gives a straight line. The higher the
temperature, the greater the gradient of the line, as the resistance falls
with increasing temperature. The same is true for an LDR with respect to
light.
Electric current 2
Electric current
Tags Done
Last edited time @October 1, 2023 9:21 AM
Components and their Characteristics
The diagrams above show some circuit components. Below: is a list of some
notes about them
A cell is a source of electrical energy. Note that a battery is a
combination of cells.
The symbol for an indicator is that same as that for a light source
(including a filament lamp, but not a LED).
A LED emits light when it conducts. However, it only works in one
direction. The direction in which it conducts is called the forwards
direction.
A resistor is a component designed to have a certain resistance.
The resistance of a thermistor decreases as the temperature increases.
This is because it releases electrons and hence, increases the number
of charge carriers in the circuit.
The resistance of a LDR decreases with increasing light intensity.
Electric current 1
, Investigating the characteristics of different components.
To measure the variation of current with potential difference. You can use:
A potential divider to vary the potential difference from zero,
a variable resistor to vary the current to a minimum.
Some notable graphs.
A wire gives a straight line through the origin showing that Ris a
constant value for any current. The resistance can be obtained by
calculating the reciprocal of the gradient. A resistor is also a straight line.
A filament bulb gives a curve with a decreasing gradient because its
resistance increases as it becomes hotter. This is because a higher
current is flowing through the bulb.
A thermistor at constant temperature gives a straight line. The higher the
temperature, the greater the gradient of the line, as the resistance falls
with increasing temperature. The same is true for an LDR with respect to
light.
Electric current 2
