AC and DC Circuits

Basics

Series and parallel circuits

  • Consider the following image
2iom76.png
  • Voltage:
    • In a series circuit, the total voltage is the sum of all the voltages.
      • That is: $V_{output} = V_1+V_2+...$
      • In the example, the voltage output would be 12V
      • For a circuit with resistors in it, this means that the voltage drop across each resistor adds up to the supply voltage.
    • In a parallel circuit, the total voltage is equal to the voltage in any circuit.
      • That is: $V_{output} = V_1 = V_2 = ...$
      • In the example, the voltage output would be 6V
      • For a circuit with resistors in it, this means that the voltage drop across each resistor is equal to the supply voltage.
  • Current
    • In a series circuit, the total current is equal to the current from one battery.
      • That is $I_{output} = I_1 = I_2 = ...$
      • In the example, the output would be 20A
      • For a circuit with resistors in it, this means that the same current flows through each resistor.
    • In a parallel circuit, the total current is the sum of all the currents.
      • That is: $I_{output} = I_1+I_2+...$
      • In the example, the output would be 40A
      • For a circuit with resistors in it, this means that the current flowing through each resistor adds up to the supply current.
  • Resistance
    • $R_{series} = R_1+R_2+R_3...$
    • $\frac{1}{R_{parallel}} = \frac{1}{R_{1}} + \frac{1}{R_{2}} + \frac{1}{R_{3}} + ... + \frac{1}{R_{n}}$

Rectification

  • This is the conversion of AC to DC
  • For a Half-Wave rectification, a single diode is used to block the one direction of the AC wavelength.
500px-Halfwave.rectifier.en.svg.png
  • For Full-Wave rectification, four diodes are used to produce a current in a single direction.
500px-Gratz.rectifier.en.svg.png

* These four diodes are arranged as shown (This is known as a bridge rectifier):

1ihpx5.png