Resistors
Types
Fixed Resistors
Variable Resistors
Thermistors
Varistors
Light Dependent Resistors
Magneto-resistors
Application
used in modulators
used for controlling temperature
used in digital multi-meter
step up or lower the voltage
device used in electrical circuits
two-terminal electrical component
unit of resistors
Ohm
resistors in series
Rtotal = R1 + R2 + R3 +……+Rn
Resistors in Parallel
1/Rtotal= 1/R1+1/R2+1\R3+.........+1/RN
Colour code
used to identify the values of resistors
specify the resistance value
tolerance
Main topic
Resistance
measure of the opposition to current flow
electrical component
Unit
Ohm
volt per ampere.
resistance of conducting material
directly proportional to the length of the material
inversely proportional to the cross-sectional area of the material
depends on the nature of the material
It depends on the temperature
Resistance Formula 1
Ohm’s Law
V = I * R
ratio of supply voltage and current.
Resistance Formula 2
Power and Voltage
P=V*I
product of supply voltage and electric current.
Types of resistance
AC Resistance
overall resistance in AC circuits
Resistance = Impedance
R = Z
DC Resistance
magnitude of DC is constant
R = Z
no frequency in DC circuits
E-SERIES
Standard resistors values
Types
E3 series
three values: 1, 2.2 and 4.7
E6 series
six values: ±20% tolerance
E12 series
12 values: ±10% tolerance
E24 series
24 values: ±5% tolerance