Reading data sheets, signal diodes

Discussion in 'General Electronics Chat' started by hp1729, Sep 5, 2016.

  1. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
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    Reading data sheets
    Signal Diodes
    1N4148

    Absolute maximum ratings

    Continuous reverse voltage – 75 V
    This is the maximum voltage the device can work at. Above this the diode may be damaged.

    Continuous forward current – 200 mA
    This is the maximum forward biased current that can be sustained.

    Repetitive peak forward current – 450 mA
    This is the maximum forward biased current under pulse conditioned.

    Non-repetitive peak forward current – 4 A for 1 µs, 1 Amp for 1 ms, 500 mA for 1 s.
    This is the maximum forward biased current under single pulse conditioned.

    Total power dissipation – 500 mW
    Forward current times forward voltage drop should not exceed this value or the diode will likely be damaged.


    Working electrical characteristics

    Forward voltage – 0.62 to 0.72 at 5 mA, 1 V at 10 mA maximum
    This is the voltage across the diode when forward biased at given current levels. At currents of µA it may be a fraction of this, like 0.15 V maybe.
    Given this characteristic the effective resistance varies as current varies.

    Reverse current – 25 nA, maximum
    This is the current that will leak through the diode when reverse biased under stated conditions of voltage and temperature.

    Diode capacitance – 4 pF
    When reverse biased it will have an effective capacitance. It will store a small charge when switching from forward biased to reverse biased.

    Reverse recovery time – 4 ns
    When switching from forward biased to reverse biased this is the delay time under stated conditions. See figure 7.

    Forward recovery voltage – 2.5 V
    When switching from off to on the forward voltage will not immediately drop to the expected 600 mV or so. It will peak to this voltage then drop to the minimum within the recovery time. See figure 8.

    Figure 2
    Maximum forward current at a given temperature. Below room temperature (25° C) it can safely pass as much as 200 mA continuously. As temperature of the diode increases this limit decreases.

    Figure 3
    Forward voltage at different levels of forward current and how it changes at different temperatures.

    Figure 4
    Maximum once in a while pulse current with respect to pulse width.

    Figure 5
    Expected reverse current leakage at different temperatures.

    Figure 6
    Diode capacitance as a factor of reverse voltage.

    Figure 7
    This graph shows the conditions given for reverse Recovery time. When the diode switches from on to off the voltage will not increase instantly.

    Figure 8
    This graph shows the conditions for Forward Recovery voltage. When the diode switches from off to on the forward voltage does not instantly drop to the expected 600 mV, or so. It will peak at some voltage and eventually drop to the expected voltage in the stated switching time.
     
    Last edited: Sep 5, 2016
  2. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,941
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    Should be 200mA.
     
  3. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
    1,951
    219
    Reading data sheets
    Rectifiers
    1N400x

    Absolute maximum ratings

    1N4001 – 50 V, 1 Amp
    1N4002 – 100 V, 1 Amp
    1N4003 – 200 V, 1 Amp
    1N4004 – 400 V, 1 amp
    1N4005 – 600 V, 1 Amp
    1N4006 – 800 V, 1 Amp\
    1N4007 – 1,000 V, 1 Amp

    Continuous reverse voltage – (as stated)
    This is the maximum voltage the device can work at. Above this the diode may be damaged.

    Continuous forward current – 1 A
    This is the maximum forward biased current that can be sustained.

    Non-repetitive peak forward current – 30 A for 8.3 ms
    This is the maximum forward biased current under single pulse conditioned.

    Total power dissipation – 3 W
    Forward current times forward voltage drop should not exceed this value or the diode will likely be damaged.

    Working electrical characteristics

    Forward voltage – 1.1 V at 1 A maximum
    This is the voltage across the diode when forward biased at given current levels. At currents of mA it may be a fraction of this, like 300 mV maybe.
    Given this characteristic the effective resistance varies as current varies.

    Reverse current – 30 µA, maximum
    This is the current that will leak through the diode when reverse biased under stated conditions of voltage and temperature.

    Diode capacitance – 15 pF
    When reverse biased it will have an effective capacitance. It will store a small charge when switching from forward biased to reverse biased.

    Reverse recovery time – ?
    (Pretty useless above audio.)

    Forward recovery voltage – ?
    (Pretty useless above audio.)

    Figure 2
    Maximum forward current at a given temperature. Below 80° C it can safely pass as much as 1 A continuously. As temperature of the diode increases this limit decreases.

    Figure 3
    Forward voltage at different levels of forward current.

    Figure 4
    Maximum once in a while pulse current with respect to pulse width.

    Figure 5
    Expected reverse current leakage at different temperatures.
     
  4. paulktreg

    Distinguished Member

    Jun 2, 2008
    611
    120
    Why are you repeating what is stated on the datasheet?
     
  5. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,346
    Hello,

    Have a look at the PDF.

    Bertus
     
  6. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
    1,951
    219
    Yes, I noticed the error and corrected it.
     
  7. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
    1,951
    219
    Superbly done.
     
  8. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
    1,951
    219
    We still get people who just don't grasp even the simple points.
    I didn't see a way to cover the subject on the level the posters are at. 1,000 word essays on an engineering level don't help everybody.
     
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