ohm

Examples of ohm in the following topics:

• Ohm's Law

  • This important relationship is known as Ohm's law.
  • The unit for resistance is the ohm where 1Ω = 1 V/A.
  • This relationship is also called Ohm's law.
  • Ohm's law (like Hooke's law) is not universally valid.
  • The other two devices do not follow Ohm's law.

• Current and Voltage Measurements in Circuits

  • According to Ohm's law, The electrical current I, or movement of charge, that flows through most substances is directly proportional to the voltage V applied to it.
  • Ohm's law can therefore be written as follows:
  • More specifically, Ohm's law states that R in this relation is constant, independent of the current.
  • To solve this problem, we would just substitute the given values into Ohm's law: I = 1.5V/5Ω; I = 0.3 amperes.
  • If we know the current and the resistance, we can rearrange the Ohm's law equation and solve for voltage V:

• Resistors in AC Circuits

  • In a circuit with a resistor and an AC power source, Ohm's law still applies (V = IR).
  • Ohm's law applies to AC circuits as well as to DC circuits.
  • Apply Ohm's law to determine current and voltage in an AC circuit

• Capacitors in AC Circuits: Capacitive Reactance and Phasor Diagrams

  • There, we used the Ohm's law (V=IR) to derive the relationship between voltage and current in AC circuits.
  • In this and following Atoms, we will generalize the Ohm's law so that we can use it even when we have capacitors and inductors in the circuit.
  • Because it is still a voltage divided by a current (like resistance), its unit is the ohm.
  • This is considered to be an effective resistance of the capacitor to AC, and so the rms current Irms in the circuit containing only a capacitor C is given by another version of Ohm's law to be $I_{rms} = \frac{V_{rms}}{X_C}$, where Vrms is the rms voltage.
  • Note that XC replaces R in the DC version of the Ohm's law.

• Resisitors in Series

  • Using Ohm's Law to Calculate Voltage Changes in Resistors in Series
  • According to Ohm's law, the voltage drop, V, across a resistor when a current flows through it is calculated by using the equation V=IR, where I is current in amps (A) and R is the resistance in ohms (Ω).

• Resistors in Parallel

  • According to Ohm's law, the currents flowing through the individual resistors are $I_1 = \frac{V}{R_1}$, $I_2 = \frac{V}{R_2}$, and $I_3 = \frac{V}{R_3}$.

• Inductors in AC Circuits: Inductive Reactive and Phasor Diagrams

  • The rms current Irms through an inductor L is given by a version of Ohm's law: $I_{rms} = \frac{V_{rms}}{X_L}$ where Vrms is the rms voltage across the inductor and $X_L = 2\pi \nu L$ with $\nu$ the frequency of the AC voltage source in hertz.
  • Because the inductor reacts to impede the current, XL has units of ohms (1 H=1 Ωs, so that frequency times inductance has units of (cycles/s)(Ωs)=Ω), consistent with its role as an effective resistance.

• Introduction and Importance

  • Kirchhoff, rather, used Georg Ohm's work as a foundation for Kirchhoff's current law (KCL) and Kirchhoff's voltage law (KVL).

• RLC Series Circuit: At Large and Small Frequencies; Phasor Diagram

  • By combining Ohm's law (Irms=Vrms/Z; Irms and Vrms are rms current and voltage) and the expression for impedance Z, from:

• Poiseuille's Equation and Viscosity

  • Poiseuille's equation as given in this example (see ) is analogous to Ohm's equation for determining the resistance in an electronic circuit and is of great practical use in hydraulic-circuit analysis.