Current and Charge

Current

Flow of electric charge

Circuit

Path around which current flows.

Electrical Conductor

Substance through which current can flow.

e.g. silver, copper, aluminum, water, human body, ground, etc.

Insulator

Substance through which current cannot flow.

e.g. glass, plastic, rubber, air, etc.

Electric Current in a Metal Conductor

Flow of electrons in a metal.

Q=ItQ=It

charge gone past = current x time taken

SI Unit: ampere (A)

1 ampere = 1 coulomb passing per second

Direct Current

  • Current that flows in one direction only.

Alternating Current

  • Current that reverses direction every so often.


sum of currents leaving junction = sum of currents flowing into junction

 

I1+I2=I3+I4I_1+I_2=I_3+I_4


  • Measured wtih ammeter that is connected in series.

  • Current is the same at every point in a series circuit.