Monday, June 15, 2015

SIM CARD


Image result for sim card

SIM CARD
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Sunday, June 14, 2015

RESISTOR

RESISTOR
Image result for working of a resistor
basics
a simple ohm law

v= I R
  • resistance reduces or limits currents
  • divides the voltage
  •  resistance is measured in ohms (Ω)
  • converts electrical energy into heat which is dissipated into the air where this principle is used in a iron box resistor is used as a heating element
what is a current
Image result for current
  • move of electrons inside a atom ie electrons when charged move towards a hole to ocupy it ,it constitutes to a current
  •  current is measured in ampere (A)
  • current is always directed from positive to negative terminal
  • or entering of current is always positive
  • where as leaving end is always negative
what is a voltage
Image result for potential difference voltage
  • potential difference between the two ends
  • measured in volt(v)
TYPES OF RESISTANCE
  1. Fixed resistance-resistance value is fixed
  • carbon film tolerance(5%,10%)
  • metal film(1%,2%)
  • wire wound
  1. variable resistance -resistance r so small to write values therefore colored need color coding
table
Image result for resistor color code
RESISTANCE COLOR CODING
 
 
 
 
 
 here colors are
  1.  brown  1st value
  2. black     2nd value
  3. orange  multiplier
  4. yellow tolerance
values taken from the table
brown 1
black   0
orange 1000
yellow +or - 3%
 10*10^3 tolerance +or - 3%