Circuits

• Series Circuits

  • In a series circuit, components are connected to each other in a line
  • Current is the same at any point
  • If a component is disconnected from a series circuit, all the other components in the circuit will also stop working
  • Series circuits are innappropriate for most applications
  • Rarely used for domestic situations, such as lighting or heating
• Components in circuits

  .

  A) Open switch

  B) Closed switch

  C) Cell

  D) LED (Light emmiting diode)

  E) Fixed resistor

  F) Filament lamp

  G) Fuse

  H) Voltmeter (parallel)

  I) Ammeter (series)

  J) Thermistor

  K) LDR (Light dependent resistor)

  L) Diode (AC circuit only)

  M) Every component is considered a RESISTOR!!!

  N) Take energy & slow current down

  
• Types of Current

  AC = Alternating Current

  DC = Direct Current
• Diodes

  • Froce electrons to flow in only 1 direction based on the direction its facing

  A) AC

  B) Conventional Current

  C) + --> -

  
• Series Circuits and Current

  • The amount of current flowing through a circuit depends on the level of voltage supplied
  • Increased voltage will drive more current through the circuit
  • Amount of current flowing through a circuit depends on the number of components
  • Increasing number of components increases the resistance in the circuit
  • Current is measured using an Ammeter
  • In Amps
  • Placed in series
  • Lamps & LED's can be used to estimate the current
  • If current is high, the lamp will glow brightly
• Charge, Current and Time

  • Current: The rate of flow of electrical charge
  • Charge is measured in coulumbs (C)

  Q = It Q = Charge (C)

  I = Current (A)

  t = Time (S)

  A) Charge, Q (C)

  B) Current, I (a)

  C) Time, t (S)

  
• Current at Junctions

  • Series
  • Means that the components in the circuit are connected to each other, in a line
  • Parallel
  • Each component is attached to the power supply separately
  • Parallel circuits contain junctions
  • Where wires branch off in a circuit
  • Each junction is likely to contain its own components
  • Current is conserved at junctions
  • The total current (I total) of a circuit is the sum of the currents found at each junction (I₁ and I₂ and so on)
• Voltage in Series & Parallel Circuits

  • Series ==> voltage is shared across all components
  • Each component will recieve a fraction of total voltage
  • Parallel ==> voltage is the same across all components
  • Each junction - full v. produced by battery
• Resistors in Parallel Circuits

  1/Rt = 1/R₂ + 1/R₂
• Energy Transfer

  • Voltage: The energy transferred per unit of charge passed
  • Defined as 1 joule per coulomb

  E = QV E = Energy Transferred (J)

  Q = Charge (C)

  V = Voltage (V)

  A) E (J)

  B) Q (C)

  C) V (V)