Capacitive Impedance Formulas and Characteristics

Capacitive Impedance

• Definition: Capacitive impedance (Zc) is the opposition to the flow of an AC current by a capacitor.
• Formula: Zc = 1 / (2 * π * f * C), where:
  • Zc is the capacitive impedance (in ohms, Ω)
  • f is the frequency of the AC signal (in hertz, Hz)
  • C is the capacitance (in farads, F)
• Key characteristics:
  • Zc is inversely proportional to the frequency of the AC signal
  • Zc is inversely proportional to the capacitance
  • Zc decreases as frequency increases
  • Zc increases as capacitance decreases
• Phase Angle: The current in a capacitor leads the voltage by 90 degrees (π/2 radians) in a purely capacitive circuit.
• Impedance Triangle: The capacitive impedance (Zc) is one of the three components of the impedance triangle, along with resistive impedance (R) and inductive impedance (ZL).
• Importance: Understanding capacitive impedance is crucial in the design and analysis of AC circuits, filters, and resonant circuits.

Capacitive Impedance

• Definition: Capacitive impedance is the opposition to the flow of an AC current by a capacitor.

Formula and Components

• Zc = 1 / (2 * π * f * C)
• Zc is the capacitive impedance (in ohms, Ω)
• f is the frequency of the AC signal (in hertz, Hz)
• C is the capacitance (in farads, F)

Key Characteristics

• Zc is inversely proportional to the frequency of the AC signal
• Zc is inversely proportional to the capacitance
• Zc decreases as frequency increases
• Zc increases as capacitance decreases

Phase Angle

• The current in a capacitor leads the voltage by 90 degrees (π/2 radians) in a purely capacitive circuit

Impedance Triangle

• The capacitive impedance (Zc) is one of the three components of the impedance triangle
• The other components are resistive impedance (R) and inductive impedance (ZL)

Importance

• Understanding capacitive impedance is crucial in the design and analysis of AC circuits, filters, and resonant circuits

Ohm's Law and Current Calculation

• Ohm's Law states that current (I) is directly proportional to voltage (V) and inversely proportional to resistance (R).
• The formula to calculate current is I = V / R.
• Current is measured in amperes (A).

Key Points to Remember

• Increasing the voltage or decreasing the resistance increases the current.
• Decreasing the voltage or increasing the resistance decreases the current.

Example Calculations

• If a circuit has a voltage of 12V and a resistance of 4Ω, the current is 3A (I = V / R = 12V / 4Ω = 3A).
• If a circuit has a current of 2A and a resistance of 6Ω, the voltage is 12V (V = I × R = 2A × 6Ω = 12V).