Diode Question

Discussion in 'General Electronics Chat' started by Engr, Sep 17, 2011.

  1. Engr

    Thread Starter Member

    Mar 17, 2010
    114
    5
    Hi Guys,

    I have a diode question. I was searching the internet for diode application notes and I saw these items "rectifier diode" and "switching diode". I read their definition and as what I understand the difference between the two is only on their application. I want to ask, what is really the difference between the "rectifier diode" and "switching diode"?
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Switching diodes like the 1N914 and 1N4148 have extremely fast switching/recovery times, on the order of 4-5nS. Rectifier diodes, like the 1N4000 series and 1N5400 series are extremely slow by comparison; they are only suitable for slow waveforms (up to around 400Hz) as their recovery times are many orders of magnitude slower; and their turn-on times are unspecified.

    A while back, I excerpted this chart from a Rohm news article; you may find it helpful:
    [​IMG]

    In the chart, there really isn't an equivalent of the 1N914/1N4148 "switching diode", but it's in the same range as the top Schottky barrier diode; and a "rectifier diode" is a "Si Standard Recovery Diode".

    Link to article: http://www.rohm.com/news/pdf/rohm_sic_diodes_cna110004_wp.pdf
    The article is very informative, and worth the time spent reading it.
     
    Last edited: Sep 17, 2011
    PackratKing likes this.
  3. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    And not only speed i.e. switching time but usually a switching diode is a much lower power device than a rectifier. There can be quite a bit of overlap but a rectifier diode kind of hints at changing AC to DC for a power application. A switching doide typically is smaller, faster and lower current; a rectifier frequently larger, slower and capable of conducting higher current.
    Wookie, I like your chart.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I can't take credit for it; it's simply cropped directly from the article.

    I ran across the article while researching SiC (Silicon Carbide) diodes; they are a relatively new technology that was first developed by Cree. SiC diodes are quite difficult to make, but are essentially high-voltage versions of Schottky diodes; they have extremely fast recovery times, which is very important for building efficient high voltage supplies/dc-dc inverters.
     
    Engr likes this.
  5. Engr

    Thread Starter Member

    Mar 17, 2010
    114
    5
    Thanks for the very informative reply.
     
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