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{{title|Diode}}
 
{{title|Diode}}
 
A '''diode''' is a two-[[terminal]] [[electronic device]] that permits the flow of [[current]] primarily in one direction.
 
A '''diode''' is a two-[[terminal]] [[electronic device]] that permits the flow of [[current]] primarily in one direction.
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== Overview ==
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A diode is a two-[[terminal]] [[electronic device]] that allows [[current]] to flow in just one direction. When flowing in the ''forward-biased direction'', the diode acts as a [[wire]] with very low [[resistance]], creating a short-like condition. Attempting flow in the ''reverse-biased direction'' will result in a very high resistance, prohibiting the flow of current, creating an open circuit condition.
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== Ideal Diode ==
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The [[current-voltage characteristic]] of an '''[[ideal device|ideal]] diode''' is shown below.
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:[[File:ideal diode i-v.svg|400px]]
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The forward resistance (<math>R_f</math>) of the ideal diode can be obtained through [[Ohm's law]] where the forward voltage (<math>V_f</math>) across the diode is 0 (given from the I-V curve above) and the forward current (<math>I_f</math>) is any amount of current.
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:<math>R_f = \frac{V_f}{I_f} = \frac{0 \text{V}}{\text{Any positive current (e.g., 5 mA)}} = 0 \Omega</math>
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When conducting, an ideal diode acts as a wire with 0 Ω of [[resistance]]. In other words, in the forward-biased direction, an ideal diode is a [[short circuit]].
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:[[File:ideal diode forward biased.svg|300px]]
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For the reverse-biased resistance (<math>R_f</math>), the reverse voltage (<math>V_r</math>) across the diode is any negative value and the reverse current (<math>I_r</math>) is 0.
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:<math>R_r = \frac{V_r}{I_r} = \frac{\text{Any negative voltage (e.g., -1.5 V)}}{0 \text{mA}} = \infty \Omega</math>
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When resisting, an ideal diode acts as a wire with ∞ Ω of [[resistance]]. In other words, in the reverse-biased direction, an ideal diode is an [[open circuit]].
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:[[File:ideal diode reverse biased.svg|300px]]
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The above can be expressed as a step function.
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:<math>
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I_D =
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\begin{cases}
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  0, & V_D\leq 0 \\
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  \infty, & V_D> 0
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\end{cases}
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</math>
  
  
 
{{stub}}
 
{{stub}}
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[[Category:electronic components]]

Latest revision as of 01:39, 6 August 2018

A diode is a two-terminal electronic device that permits the flow of current primarily in one direction.

Overview[edit]

A diode is a two-terminal electronic device that allows current to flow in just one direction. When flowing in the forward-biased direction, the diode acts as a wire with very low resistance, creating a short-like condition. Attempting flow in the reverse-biased direction will result in a very high resistance, prohibiting the flow of current, creating an open circuit condition.

Ideal Diode[edit]

The current-voltage characteristic of an ideal diode is shown below.

ideal diode i-v.svg

The forward resistance ( Equation upper R Subscript f ) of the ideal diode can be obtained through Ohm's law where the forward voltage ( Equation upper V Subscript f ) across the diode is 0 (given from the I-V curve above) and the forward current ( Equation upper I Subscript f ) is any amount of current.


Equation upper R Subscript f Baseline equals StartFraction upper V Subscript f Baseline Over upper I Subscript f Baseline EndFraction equals StartFraction 0 upper V Over Any positive current left-parenthesis e period g period comma 5 mA right-parenthesis EndFraction equals 0 normal upper Omega


When conducting, an ideal diode acts as a wire with 0 Ω of resistance. In other words, in the forward-biased direction, an ideal diode is a short circuit.

ideal diode forward biased.svg

For the reverse-biased resistance ( Equation upper R Subscript f ), the reverse voltage ( Equation upper V Subscript r ) across the diode is any negative value and the reverse current ( Equation upper I Subscript r ) is 0.


Equation upper R Subscript r Baseline equals StartFraction upper V Subscript r Baseline Over upper I Subscript r Baseline EndFraction equals StartFraction Any negative voltage left-parenthesis e period g period comma hyphen 1.5 upper V right-parenthesis Over 0 mA EndFraction equals normal infinity normal upper Omega

When resisting, an ideal diode acts as a wire with ∞ Ω of resistance. In other words, in the reverse-biased direction, an ideal diode is an open circuit.

ideal diode reverse biased.svg

The above can be expressed as a step function.

Equation upper I Subscript upper D Baseline equals StartLayout Enlarged left-brace 1st Row 1st Column 0 comma 2nd Column upper V Subscript upper D Baseline less-than-or-equal-to 0 2nd Row 1st Column normal infinity comma 2nd Column upper V Subscript upper D Baseline greater-than 0 EndLayout


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