Electricity Flashcards
Electric current
Collective motion of particles carrying electric charge. This requires the relatively free motion of the charge carriers
Conductor
Material that contains charge carriers which can move freely
Insulator
No freely moving charge carriers
Direct current
Current that is constant in time
Alternating current
The current changes as a sine function over time
Direction of current ( conventional current direction)
Defined by the flow direction of the positive charges
Electric current
Amount of charge passing through a given cross section of a conductor divided by the time elapsed
SI unit for electric current (I)
Ampere
What does the electric current in a conductor depend on?
Strength of the electric field moving the charge carriers
Ohms law
The electric current in a conductor is proportional to the voltage between its two poles
Electric resistance is a constant, why?
It does not depend on voltage
SI unit for resistance (R)?
Ohm
In a long conductor the motion of charges will be
Slower and electric current lower
In a longer conductor the resistance is
Bigger
A big cross section area of a conductor gives … current and .. resistance.
Higher.. lower
Joule heating
The accelerating work of the electric field will finally increase the thermal motion of the particles. It turns into thermal energy and the conductor becomes hotter
Kirchoffs current law
Junction law/first law
Currents flowing into a junction are equal to the currents flowing out of that junction.
Kirchoffs voltage law
Loop law/second law
The directed sum of voltages of electrical components along a loop within an electrical circuit is zero. Voltage is partitioned between the electrical components.
RC circuit
Electric circuit containing an ohmic resistor and a capacitor.
