Name: diode current and reverse bias
Uploaded: 2023-09-18T17:11:16.000Z
Duration: 51 s
Channel: JoVE

K12 Standards

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North Carolina K-12 Science Standard Course of Study

9-12

Physical Science

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Motion and Stability- Forces and Interactions

PS.PSc.6.2

Non-ohmic Devices

Qualsiasi dispositivo che non presenti una relazione lineare tra tensione e corrente è noto come dispositivo non ohmico. Ad esempio, un diodo è un elemento semiconduttore che non obbedisce alla legge di Ohm e consente alla corrente di fluire in una direzione.
Un grafico della corrente rispetto alla tensione può essere utilizzato per studiare il comportamento di un diodo. Il diodo conduce quando la tensione che lo attraversa è positiva e superiore a 0,7 volt. La corrente attraverso il diodo aumenta all'aumentare della tensione applicata, ma la tensione attraverso il diodo rimane di circa 0,7 volt.
Quando la polarità del diodo è invertita, una corrente trascurabile scorre attraverso il diodo; una volta raggiunta la tensione di rottura, il diodo inizia a condurre.

<ol>
	<li>OpenStax. (2019). Fisica universitaria Vol. 2. [Versione web], Pg 396 - 398. Estratto da <a href="https://openstax.org/books/university-physics-volume-2/pages/9-3-resistivity-and-resistance">https://openstax.org/books/university-physics-volume-2/pages/9-3-resistivity-and-resistance</a></li>
</ol>

dispositivi non-ohmici

Nella maggior parte delle sostanze, il flusso di corrente è proporzionale alla tensione applicata ad essa. Una relazione semplice tra i valori di corrente, tensione e resistenza è nota come legge di Ohm. I dispositivi non ohmici non mostrano una relazione lineare tra tensione e corrente. Uno di questi dispositivi è l'elemento circuitale semiconduttore noto come diodo. Un diodo è un dispositivo di circuito che consente il flusso di corrente in una sola direzione.

Considera un circuito semplice composto da una batteria, un diodo e una resistenza. Un diodo è composto da due terminali: un anodo (terminale positivo) e un catodo (terminale negativo). Quando l'anodo è collegato al potenziale negativo e il catodo al potenziale positivo, si dice che il diodo è polarizzato inversamente. Con la polarizzazione inversa, il diodo ha una resistenza estremamente elevata e c'è un flusso di corrente molto limitato - essenzialmente zero corrente attraverso il diodo e la resistenza. Man mano che la tensione applicata al circuito aumenta, la corrente rimane essenzialmente zero fino a quando la tensione non raggiunge la tensione di rottura e il diodo conduce la corrente. La tensione di rottura è definita come la più grande tensione inversa che può essere applicata senza causare un aumento esponenziale della corrente di dispersione in un diodo. Quando la batteria e il potenziale attraverso il diodo vengono invertiti, rendendo l'anodo positivo e il catodo negativo, il diodo conduce e la corrente scorre attraverso il diodo se la tensione è maggiore di 0,7 V. La resistenza del diodo è vicina allo zero. Un grafico può essere tracciato tra corrente e tensione, che mostra che tensione e corrente non hanno una relazione lineare.

Dispositivi non-Ohmici

Nella maggior parte delle sostanze, il flusso di corrente è proporzionale alla tensione ad esso applicata. Una semplice relazione tra i valori di corrente, tensione e ...

Education

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JoVE Core

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Unit 1

Unità 1

Current and Resistance

Corrente e Resistenza

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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 diode’s direction changes how the circuit behaves.

When the anode is connected to the negative potential and the cathode is connected to the positive potential, the diode is reverse biased. In this case, the diode has extremely large resistance, so very little current flows. The current through both the diode and the resistor is essentially zero.

As the applied voltage increases in reverse bias, the current stays near zero until the breakdown voltage is reached. Breakdown voltage is the largest reverse voltage that can be applied without causing an exponential increase in leakage current in a diode. When the battery and the diode’s potential are reversed so the anode is positive and the cathode is negative, the diode conducts. If the voltage is greater than 0.7 V, current flows through the diode and its resistance is close to zero. A graph of current versus voltage shows this non-linear behavior clearly.

Diode Current and Reverse Bias

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...

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resistivity

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resistance

Factors That Affect Electrical Resistance

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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

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...

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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...

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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 a diode behaves in reverse bias and forward bias, why it is nonohmic, and how its current-voltage graph differs from Ohm’s law.

Diode Current and Reverse Bias | JoVE K12

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PS.Phy.4.3

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Ohio’s Learning Standards and Model Curriculum

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

Alabama Course of Study Science

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Waves and Their Applications in Technologies for Information Transfer

9-12.PS.2.3.c

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9-12.P.2.6.b

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Diode Current and Reverse Bias

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