Name: measuring current, voltage, and resistance
Uploaded: 2023-04-30T12:39:07.000Z
Duration: 1 min 21 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Physical Science

motion-and-stability-forces-and-interactions

Motion and Stability- Forces and Interactions

PS.PSc.6.2

Ohm's Law

En 1827, un físico alemán, Georg Simon Ohm, demostró experimentalmente la ley de Ohm.
La ley de Ohm establece que la corriente que pasa a través de un material es directamente proporcional al voltaje a través del dispositivo en condiciones ambientales constantes.
Cualquier material que obedezca la ley de Ohm se conoce como material óhmico, mientras que si no obedece a la ley de Ohm, se conoce como material no óhmico.
Considere otra configuración experimental para demostrar la ley de Ohm, que consta de una resistencia, una fuente de alimentación, un interruptor, un voltímetro y un amperímetro. El voltaje a través de la resistencia se mide con un voltímetro, mientras que la corriente en línea con la resistencia se mide con un amperímetro.
Cuando la resistencia está conectada a la fuente de alimentación, la corriente fluye en el sentido de las agujas del reloj y el voltímetro y el amperímetro muestran lecturas positivas. Por el contrario, cuando se conmutan los cables de la fuente de alimentación, la corriente fluye en sentido contrario a las agujas del reloj, lo que da como resultado lecturas negativas.
Un gráfico trazado entre las lecturas de voltaje y corriente se encuentra lineal. La pendiente de la línea da la resistencia, confirmando que la resistencia es un dispositivo óhmico.

<ol>
	<li>OpenStax. (2019). Física Universitaria Vol. 2. [Versión web], págs. 396-398. Obtenido de <a href="https://openstax.org/books/university-physics-volume-2/pages/9-4-ohms-law">https://openstax.org/books/university-physics-volume-2/pages/9-4-ohms-law</a></li>
</ol>

ley de ohm

Muchos materiales presentan una relación simple entre los valores de corriente, voltaje y resistencia, conocida como la ley de Ohm. La corriente que fluye a través de la mayoría de las sustancias es directamente proporcional al voltaje aplicado a ellas. El físico alemán Georg Simon Ohm (1787-1854) fue el primero en demostrar experimentalmente que la corriente en un alambre metálico es directamente proporcional al voltaje aplicado. Cualquier material, componente o dispositivo que cumple con la ley de Ohm, donde la corriente a través del dispositivo es proporcional al voltaje aplicado, se conoce como un material ohmico o componente ohmico. Cualquier material o componente que no cumple con la ley de Ohm se conoce como un material no ohmico o componente no ohmico. En un artículo publicado en 1827, Georg Ohm describió un experimento en el que midió el voltaje y la corriente a través de varios circuitos eléctricos simples que contenían diferentes longitudes de alambre. El experimento se utilizó para observar la corriente a través de una resistencia que resulta de un voltaje aplicado. Otro experimento similar se usó para observar la corriente a través de una resistencia que resulta de un voltaje aplicado. En este circuito simple, se conecta una resistencia en serie con una batería. El voltaje se mide con un voltímetro, que se coloca en paralelo con la resistencia. La corriente se mide utilizando un amperímetro y se coloca en serie con la resistencia. Se realizaron varias mediciones de la corriente para varios voltajes diferentes. Se midió la corriente a través de la resistencia y el voltaje a través de la resistencia, y se trazó un gráfico entre el voltaje y la corriente, que mostró una relación aproximadamente lineal. La pendiente de la línea es la resistencia, o el voltaje dividido por la corriente. El resultado se conoció como la ley de Ohm.

Ley de Ohm

Muchos materiales exhiben una relación simple entre los valores de corriente, voltaje y resistencia, conocida como ley de Ohm. La corriente que fluye ...

Education

Educación

JoVE Core

Physics

Física

Unit 1

Unidad 1

Current and Resistance

Corriente y resistencia

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

measuring current, voltage, and resistance

Ohm's law describes the relationship between current, voltage, and resistance in many materials. In these cases, the current through a substance is directly proportional to the voltage applied to it. The idea was first shown experimentally by German physicist Georg Simon Ohm, who studied current in a metal wire.

A material, component, or device that follows this pattern is called ohmic. An ohmic component has a current that increases in step with voltage. A material or component that does not follow this pattern is called nonohmic.

Ohm's 1827 experiment measured voltage across and current through simple electrical circuits with different wire lengths. The setup used a resistor connected in series with a battery. A voltmeter measured voltage in parallel with the resistor, and an ammeter measured current in series with the resistor.

Several measurements were taken at different voltages. The current through the resistor and the voltage across it were then graphed. The result was an approximately linear relationship. The slope of that line represents resistance, which is voltage divided by current, and this result became known as Ohm's law.

Measuring Current, Voltage, and Resistance

electrical current

Current Flow in Simple Circuits

Electrical current is the flow of charge in a circuit. A large current means a large amount of charge moves through a wire in a short time. A small current means only a small amount of charge moves through the circuit over a longer time. Examples include the current needed to run a refrigerator and the smaller current used by a handheld calculator. The SI unit for current is the ampere, or amp. It is named for the French physicist André-Marie Ampère (1775–1836). One ampere means one coulomb of...

drift velocity

Electrical Current and Electron Drift

Electrical current in a conductor depends on moving charges and the tiny drift speed of those charges. When a free charge enters a wire, it pushes nearby charges ahead because like charges repel each other. That push spreads through the material very quickly, so the electrical signal moves through the system at nearly the speed of light. This fast signal is not the same as the slow motion of each charge. It is a rapidly spreading change in the electric field, often described as an electrical...

current density

Current Density in Wires and Solutions

Current density describes how much electric current passes through a given cross-sectional area. It helps show not just the size of the current, but also how it is distributed through a conductor. The current density can change from point to point because the local charge flow can vary. If the current flow is uniform, the amount of current is the same at every point along the conductor, even when the conductor’s area changes. Current density is measured in amperes per square meter. Its...

resistivity

Resistivity in Conductors and Insulators

Resistivity describes how much a material opposes electric current. When a voltage is applied to a conductor, an electric field forms. The charges in the conductor feel that force, and a current density develops. In some materials, including metals at a given temperature, the current density is approximately proportional to the electric field. In those cases, current density can be modeled with conductivity, written as sigma. Electrical conductivity is measured in (ohm·m)^−1. It tells how well...

resistance

Factors That Affect Electrical Resistance

Electrical resistance describes how much a conductor opposes the flow of current. It is represented by R. When current passes through a conductor, heat is also produced. Resistance is tied to the material’s resistivity, which is a property of the material used to make an electrical component. Resistance is different from resistivity. Resistivity belongs to the material itself, while resistance belongs to the finished component. To study this relationship, consider a wire with length L,...

ohm's law

Ohm's law describes the relationship between current, voltage, and resistance in many materials. In these cases, the current through a substance is directly proportional to the voltage applied to it. The idea was first shown experimentally by German physicist Georg Simon Ohm, who studied current in a metal wire. A material, component, or device that follows this pattern is called ohmic. An ohmic component has a current that increases in step with voltage. A material or component that does not...

non-ohmic devices

Diode Current and Reverse Bias

A diode is a nonohmic circuit element that makes current and voltage behave differently from Ohm’s law. In most substances, current is proportional to the voltage applied, but a diode does not show a linear current-voltage relationship. A diode is a semiconducting device with two terminals: an anode, which is the positive terminal, and a cathode, which is the negative terminal. It allows current to flow in only one direction. In a simple circuit with a battery, a diode, and a resistor, the...

electrical power

Power Limits in Electrical Circuits

Electrical power in a circuit depends on current and voltage. It is the product of these two values and is measured in watts, or joules per second. That relationship helps explain how much energy a circuit can deliver. A car’s auxiliary power outlet is one real-world example. Some outlets are rated at 20 amps and 12 volts, so they can deliver a maximum of 240 watts. That rating shows the upper limit of power the circuit can provide to devices such as a cell phone charger. Bulb wattage also...

electrical energy

Cutting Electric Bills with Efficient Lighting

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continuity equation

Charge Conservation and Current Flow

Charge conservation and current flow are linked through the continuity equation. The current density is the amount of current flowing per unit cross-sectional area. The current through a surface can be written as a surface integral of the current density. The conservation of charge says that the total current leaving a volume equals the rate at which charge inside that volume decreases. The total charge can be written using volume charge density, which is a space function. Because of this, the...

boundary conditions for current density

Current Density at Conductivity Boundaries

Current density at a boundary changes when two conducting materials have different electrical conductivities. The normal component of current density stays continuous across the interface. The tangential component, which runs along the surface, becomes discontinuous across the boundary. Consider two conducting media with conductivities σ1 and σ2 separated by an interface. At point P1 in medium 1, the steady current density makes an angle α1 with the normal. At point P2 in medium 2, the current...

electrical conductivity

Resistance and Ohm's Law in Conductors

Resistance and Ohm's law help explain how electric current moves through a conductor. In a perfect conductor, the electric field inside is zero because free electrons move to cancel it. Any extra charge then stays on the surface. In a practical conductor, an applied electric field can remain in place. That field drives electrons through the material and creates a current. The current density, which is current per unit area, is related to the electric field. More generally, it is related to the...

theory of metallic conduction

Electron Drift in Metallic Conduction

Electron drift in metallic conduction explains how free electrons move through a conductor. A classical model can describe this motion closely, even though quantum mechanics gives the best overall picture. This model is called the theory of metallic conduction. In this theory, Newton's second law is used to find the acceleration of an electron when an electric field is applied. The electron's velocity is then found from that acceleration. The electron travels through a crystal of positive ions...

key terms and concepts

See how Ohm measured current and voltage in a simple circuit, why some materials are ohmic, and how the graph slope reveals resistance.

Measuring Current, Voltage, and Resistance | JoVE K12

physics

JoVE Core Física presenta la teoría y la aplicación de conceptos físicos fundamentales, como la cinemática, dinámica, mecánica de fluidos, estática, ondas y acústica, mediante animaciones audiovisuales concisas y fáciles de entender. Además, los vídeos de científicos en acción muestran la aplicación de los conceptos relacionados en experimentos de investigación clásicos y originales, realizados en laboratorios de todo el mundo.

PS.Phy.4.3

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Energy And Waves

Electricity

Electricity And Magnetism

DC circuits

Tennessee Academic Standards

High School

Energy

PHYS.PS3.11

PHYS.PS3.12

Virginia  Standards of Learning

HIgh School

PH.8

PH.8.b

Arizona Science Standards

HS+Phy.P4

HS+Phy.P4U1.8

Alabama Course of Study Science

waves-and-their-applications-in-technologies-for-information-transfer

Waves and Their Applications in Technologies for Information Transfer

9-12.PS.2.3.c

9-12.PS.2.3.d

9-12.P.2.6.b

9-12.P.2.6.d

Florida Department of Education

SC.912.P.10

SC.912.P.10.15

Texas Essential Knowledge and Skills

PHYS.6

PHYS.6.E

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Energy

HS-PS3-6.

Georgia Standards of Excellence

SPS10.

Ohm’s Law

SP5.

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Measuring Current, Voltage, and Resistance

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