Name: current flow in simple circuits
Uploaded: 2023-04-30T12:38:29.000Z
Duration: 1 min 10 s
Channel: JoVE

K12 Standards

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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

Electrical Current

La velocidad a la que fluye la carga es la corriente eléctrica. La unidad SI para la corriente eléctrica es el amperio, que se define como un culombio de carga que pasa a través de un área por segundo.
Considera una linterna con un interruptor, una bombilla, una batería y cables. El interruptor controla el circuito, mientras que el cable proporciona una ruta de corriente entre los componentes.
Las representaciones esquemáticas de circuitos utilizan símbolos estandarizados y líneas continuas para representar los componentes individuales del circuito y los cables de conexión.
El blub se representa como un círculo con un bucle en su interior, que indica el filamento. El interruptor se representa como dos puntos con una barra conductora y la batería como una serie de líneas largas y cortas.
Cuando el interruptor está cerrado, la linterna se enciende ya que hay una ruta completa para que la carga fluya desde el terminal positivo al negativo de la batería.
La dirección de la corriente convencional es siempre del terminal positivo al negativo, mientras que el flujo de electrones es del terminal negativo al positivo, ya que los electrones están cargados negativamente.

<ol>
	<li>OpenStax. (2019). Física Universitaria Vol. 2. [Versión web], págs. 94 - 95. Obtenido de <a href="https://openstax.org/books/university-physics-volume-2/pages/9-1-electrical-current">https://openstax.org/books/university-physics-volume-2/pages/9-1-electrical-current</a></li>
</ol>

corriente eléctrica

La corriente eléctrica se define como la tasa a la cual fluye la carga. Cuando hay una corriente eléctrica grande presente, como la utilizada para hacer funcionar un refrigerador, una gran magnitud de carga se mueve a través del cable en un corto período de tiempo. Si la corriente es pequeña, como la utilizada para operar una calculadora portátil, una pequeña magnitud de carga se mueve a través del circuito durante un largo período de tiempo. La unidad SI para la corriente eléctrica es el amperio (A), llamado así en honor al físico francés André-Marie Ampère (1775-1836). Un amperio es el flujo de un culombio de carga a través de un área en un segundo. Una corriente de un amperio resultaría de 6.25 × 1018 electrones fluyendo a través del área cada segundo. La mayoría de los electrodomésticos eléctricos tienen una clasificación en amperios (o amperios) necesarios para su correcto funcionamiento, al igual que los fusibles y los interruptores de circuito. Considera un circuito simple de una batería de automóvil, un interruptor, una lámpara de faro y cables que proporcionan un camino de corriente entre los componentes. Para que la lámpara se encienda, debe haber un camino completo para el flujo de corriente. El interruptor está ahí para controlar el circuito. Un esquema es una representación gráfica de un circuito y es muy útil para visualizar las características principales de un circuito. Los esquemas utilizan símbolos estandarizados para representar los componentes de un circuito y líneas sólidas para representar los cables que conectan los componentes. La batería se muestra como una serie de líneas largas y cortas, representando la pila voltaica histórica. La lámpara se muestra como un círculo con un bucle en el interior, representando el filamento de una bombilla incandescente. El interruptor se muestra como dos puntos con una barra conductora para conectar los dos puntos, y los cables que conectan los componentes se muestran como líneas sólidas. Cuando el interruptor está cerrado, hay un camino completo para que las cargas fluyan, desde el terminal positivo de la batería, a través del interruptor, luego a través del faro y de regreso al terminal negativo de la batería. La dirección de la corriente convencional siempre se representa en la dirección en la que fluiría la carga positiva, desde el terminal positivo al terminal negativo. Por ejemplo, en los cables metálicos, la corriente es transportada por electrones, es decir, cargas negativas. En soluciones iónicas, como el agua salada, tanto las cargas positivas como las negativas se mueven.

Corriente eléctrica

La corriente eléctrica se define como la velocidad a la que fluye la carga. Cuando hay una gran corriente presente, como la que se usa para hacer funcionar un refrigerador, un gran ...

Education

Educación

JoVE Core

Physics

Física

Unit 1

Unidad 1

Current and Resistance

Corriente y resistencia

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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 charge flows through an area in one second. A current of one amp would come from 6.25 × 10^18 electrons passing through that area each second. Most electrical appliances are rated in amperes, and fuses and circuit breakers are rated the same way for proper operation.

A simple circuit needs a complete path for current to flow. In a car battery circuit, the battery, switch, headlight lamp, and wires work together to make that path. The switch controls the circuit. When the switch is closed, charges can move from the positive terminal of the battery, through the switch, through the headlight, and back to the negative terminal.

Schematics help show this path with standard symbols. A battery is drawn as long and short lines, which represent the historic voltaic pile. A lamp is shown as a circle with a loop inside, and a switch is shown as two points with a conducting bar between them. The wires are shown as solid lines. Conventional current is drawn in the direction a positive charge would move, from positive to negative. In metal wires, electrons carry the current, so the moving charges are negative. In ionic solutions such as salt water, both positive and negative charges move.

Current Flow in Simple Circuits

electrical current

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

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...

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

Electrical energy is the energy transferred when electrons move from one point to another. The longer an appliance is used, the more electrical energy it consumes. If power stays constant, electrical energy equals the power used by the device times the time it runs. That is why longer use leads to a higher electric bill. Electric bills measure this energy in kilowatt-hours. One kilowatt-hour is equal to 3.6 × 10^6 joules. You can lower electrical energy use by cutting the time an appliance...

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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

Learn how electrical current flows in simple circuits, why amps matter, and how switches, batteries, and schematics show the path for charge.

Current Flow in Simple Circuits | JoVE K12

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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.

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Energy And Waves

Electricity

Electricity And Magnetism

DC circuits

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PS.9.b

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Waves and Their Applications in Technologies for Information Transfer

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Current Flow in Simple Circuits

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