From Electromechanical Design Handbook, Third Edition

6.2 CIRCUIT ELEMENTS

6.2.1 Basic Circuit Formulas

Resistance in series:

Resistance in parallel:

Capacitance in series:

Capacitance in parallel:

The capacitance of a parallel-plate capacitor element is given as

  • where C = capacitance, picofarads (pF)

  • K = dielectric constant of insulating medium

  • A = area of one plate, cm 2

  • n = number of plates

  • d = thickness of the dielectric, cm

If A and d are given in inches, the constant (0.0885) becomes 0.224.

Self-Inductance. In series:

In parallel:

Coupled Inductance. In series with fields aiding:

In series with fields opposing:

In parallel with fields aiding:

In parallel with fields opposing:

  • where L t = total inductance

  • M = mutual inductance

  • L 1, L 2 = self-inductance of individual coils

Mutual Inductance ( M)

  • where M = mutual inductance, same units as L A and L O

  • L A = total inductance of coils L 1 and L 2, fields aiding

  • L O = total inductance of coils L 1 and L 2, fields opposing

Resonance. The resonant frequency, or frequency at which inductive reactance ( X L) equals capacitive reactance ( X C) is given as

  • where f r = resonant frequency, Hz

  • L = inductance, H

  • C = capacitance, F

Reactance. Inductive:

Capacitive:

  • where X L = inductive reactance, ? (positive reactance)

  • X C


Products & Services
Inductance Standards and Decades
Inductance standards and decades provide highly accurate and digitally variable standard values of inductance for calibration, comparison and testing.
RF Inductors
RF inductors are special inductors designed to be used in radio frequency (RF) and microwave applications.
Capacitance Standards and Decades
Capacitance standards and decades provide a highly accurate standard value of capacitance for calibration and testing.
Electrical Inductance Sensors
Electrical inductance sensors measure the inductance of an electrical component or system.
LCR Meters
LCR meters and impedance meters measures inductance (L), capacitance (C), and resistance or impedance (R).

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