ELECTRIC CURRENT AND DIRECT CURRENT CIRCUITS
ELECTRICAL CONDUCTION
ELECTRIC CURRENT FLOWS FROM A HIGHER ELECTRIC POTENTIAL WHICH IS THE POSITIVE TERMINAL OF BATTERY TO A LOWER ELECTRIC POTENTIAL WHICH IS THE NEGATIVE TERMINAL OF BATTERY 
ELECTRIC CURRENT, I IS DEFINED AS THE TOTAL NET CHARGE, Q FLOWING THROUGH THE AREA PER UNIT TIME
THE DIRECTION OF ELECTRIC CURRENT IS FLOWING IN THE OPPOSITE DIRECTION OF ELECTRONS FLOWS
I= DQ/DT
BASE AND SCALAR QUANTITY
UNIT IS AMPERE
1 AMPERE OF CURRENT IS DEFINED AS ONE COULOMB OF CHARGE PASSING THROUGH THE
SURFACE AREA IN ONE SEC
1 AMPERE = 1 COULOMB/1 SEC = 1C/S
I=Q/T = e(nAl)/t = nevdA
WHERE Vd = 1/t = drift velocity
Hence current , I=nAvde
OHMS LAW AND RESISTIVITY
RESISTANCE IS DEFINE AS THE RATIO OF THE POTENTIAL DIFFERENCE ACROSS AN ELECTRICCAL COMPONENT TO THE CURRENT PASSING IT.
R=V/I
SCALAR QUANTITY AND ITS UNIT IS OHM
ONE OHM (1 W) IS THE RESISTANCE OF A CONDUCTOR IF THE CURRENT IN THE CONDUCTOR IS 1A WHEN A POTENTIAL DIFFERENCE OF 1V IS APPLIED ACROSS THE CONDUCTOR
RESISTIVITY IS DEFINED AS THE RESISTANCE OF A UNIT CROSS-SECTIONAL AREA PER UNIT LENGTH OF THE MATERIAL
SCALAR QUANTITY AND ITS UNIT IS OHM METER
IT IS A MEASURE OF A MATERIAL'S ABILITY TO OPPOSE THE FLOW OF AN ELECTRIC CURRENT
RESISTIVITY DEPENDS ON THE TYPE OF THE MATERIAL AND ON THE TEMPERATURE
A GOOD ELECTRIC CONDUCTORS HAVE A VERY LOW RESISTIVIES AND GOOD INSULATORS HAVE VERY HIGH RESISTIVIES
VARIATION OF RESISTANCE WITH TEMPERATURE
WHEN THE TEMPERATURE INCREASES, THE NUMBER OF FREE ELECTRONS PER UNIT VOLUME IN METAL REMAINS UNCHANGED
TEMPERATURE COEFFICIENT OF RESISTIVITY, a IS DEFINED AS A FRACTIONAL INCREASE IN RESISTIVITY OF A CONDUCTOR PER UNIT RISE IN TEMPERATURE
ELECTROMOTIVE FORCES (EMF), INTERNAL RESISTANCE AND POTENTIAL DIFFERENCE
ELECTROMOTIVE FORCE IS DEFINED AS THE ENERGY PROVIDED BY THE SOURCE (BATTERY/CELL) TO EACH UNIT CHARGE THAT FLOWS THROUGH THE EXTERNAL AND INTERNAL RESISTANCE
TERMINAL POTENTIAL DIFFERENCE IS DEFINED AS WORK DONE IN BRINGING A UNIT CHARGE FROM NEGATIVE TO THE POSITIVE TERMINALS OF THE BATTERY THROUGH THE EXTERNAL RESISTANCE ONLY
WHEN THE CURRENT I FLOWS NATURALLY FROM THE BATTERY THERE IS AN INTERNAL DROP IN POTENTIAL DIFFERENCE (VOLTAGE) EQUAL TO Ir. 
INTERNAL RESISTANCE IS DEFINE AS THE RESISTANCE OF THE CHEMICALS INSIDE THE BATTERY BETWEEN THE POLES
V=Ir
VALUE OF INTERNAL RESISTANCE DEPENDS ON THE TYPE OF CHEMICAL MATERIAL IN THE BATTERY
TOTAL EMF AND THE TOTAL INTERNAL RESISTANCE IN SERIES AND PARALLEL 
RESISTOR IN SERIES AND PARALLEL 
ELECTRICAL ENERGY AND POWER 
KIRCHOFF'S LAW
JUNCTION- A POINT IN A CIRCUIT WHERE THREE OR MORE CONDUCTOR MEET
LOOP- ANY CLOSED CONDUCTING PATH
