Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Resistive Circuits
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 2
Resistors
Resistance
Property which opposes the flow of current
R = V/I
Un...
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 3
Problem - 1
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 4
Problem - 2
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 5
Resistivity & Temperature Coefficient
( )
( )
( )20
10
2
1
0
1001
1
1
Wher...
0
R
R1
R0
R2
θ1 θ2
θ
Variation of Resistance of Copper with Temperature
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 6
Re...
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 7
Temperature Coefficients
of Resistivity
Material Temperat
ure
Coefficien
t...
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 8
Problem- 3
When a potential difference of 10 V is applied to a coil of cop...
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 9
Resistive circuits
Resistors in series:
Resistors in parallel:
R1R2
R3
321...
ELE 101 / 102 Dept of E & E Engg, MIT Manipal 10
Parallel Resistive circuits
Current Division in Parallel Circuits
( )
1 2...
Upcoming SlideShare
Loading in …5
×

L4 resistance

572 views

Published on

Published in: Business, Technology
  • Login to see the comments

  • Be the first to like this

L4 resistance

  1. 1. Resistive Circuits
  2. 2. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 2 Resistors Resistance Property which opposes the flow of current R = V/I Unit – Ohms (Ω) Power P = VI = V2 /R = I2 R Conductance Reciprocal of resistance Symbol: G Unit – Siemens (S) R V I
  3. 3. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 3 Problem - 1
  4. 4. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 4 Problem - 2
  5. 5. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 5 Resistivity & Temperature Coefficient ( ) ( ) ( )20 10 2 1 0 1001 1 1 Where 1 θα θα α θα + + = += R R RR For a homogeneous material Where = resistivity a = cross sectional area of the Resistor l = length of the Resistor ρ = Temperature coefficient of R at 0o a l R ρ=
  6. 6. 0 R R1 R0 R2 θ1 θ2 θ Variation of Resistance of Copper with Temperature ELE 101 / 102 Dept of E & E Engg, MIT Manipal 6 Resistivity & Temperature Coefficient Super Conductivity ! ( )1001 1 θα+= RR
  7. 7. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 7 Temperature Coefficients of Resistivity Material Temperat ure Coefficien t °C-1 @ 0° C Aluminum 0.00381 Copper 0.00428 Gold 0.0034 Tungsten 0.0045 Brass 0.001 Manganin 0.00002 Carbon (graphite) -0.00048 Germanium (pure) -0.048 Silicon (pure) -0.075 Material at 0° C Aluminium 2.7 * 10 -8 Copper 1.59 * 10 -8 Tungsten 5.35 *10 -8 Carbon 6500 * 10 -8 Manganin 42 * 10 -8 ρ Resistivity: Resistivity & Temperature Coefficient
  8. 8. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 8 Problem- 3 When a potential difference of 10 V is applied to a coil of copper wire of mean temperature 20° C, a current of 1.0 A flows in the coil. After some time the current falls to 0.95 A yet the supply voltage remains unaltered. Determine the mean temperature of the coil given that the temperature coefficient of resistance of copper is 4.28 * 10-3 /°C referred to 0° C. [33.5 o C]
  9. 9. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 9 Resistive circuits Resistors in series: Resistors in parallel: R1R2 R3 321 1111 RRRReq ++=
  10. 10. ELE 101 / 102 Dept of E & E Engg, MIT Manipal 10 Parallel Resistive circuits Current Division in Parallel Circuits ( ) 1 2 1 21 1 1 1 2 2 2 1 1 2 1 2 1 2 I I I R RR I I I R R R I I R R R I I R R = + + = + = = + = +

×