~ Resistors

• The resistance of components such as lamps, diodes thermistors and LDRs is not constant; it changes with the current through the component.

  The resistance of a filament lamp increases as the temperature of the filament increases.

  The current through a diode flows in one direction only. The diode has a very high resistance

  
• Resistors


  Electronic components designed to impede the flow of electric current, commonly used to control the amount of current in a circuit and to reduce voltage levels
• Symbol


  In circuit diagrams, resistors are represented by the symbol
• Resistance (R)


  A measure of how strongly a material opposes the flow of electric current, measured in ohms (Ω), the higher the resistance, the more it restricts the flow of current
• Ohm's Law


  States that the current (I) flowing through a resistor is directly proportional to the voltage (V) across it and inversely proportional to its resistance (R), expressed as V=I×R
• Types of Resistors


  • Fixed Resistors (specific resistance value, cannot be changed)
  • Variable Resistors (also known as potentiometers or rheostats, adjustable resistance)
  • Thermistors (resistance changes with temperature)
  • Light Dependent Resistors (LDR, resistance changes with light intensity)
• Color Coding


  Resistors often have colored bands to indicate their resistance value, can be decoded using a color code chart
• Power Rating


  Indicates the maximum amount of power a resistor can dissipate without damage, typically measured in watts (W)
• Series Connection


  Resistors connected end-to-end, total resistance is the sum of individual resistances: Rtotal=R1+R2+...
• Parallel Connection


  Resistors connected across common points, reciprocal of total resistance is the sum of reciprocals of individual resistances: 1/Rtotal=1/R1+1/R2+...
• Applications of Resistors


  • Voltage dividers, current limiters, signal conditioning, and more