diode design

Discussion in 'The Projects Forum' started by edmundopt, Oct 9, 2013.

  1. edmundopt

    Thread Starter Member

    May 4, 2011
    Hello again

    I need sugestions for the following schematic, the diodes D1..D4, when the DC voltage applyed is inverted the circuit shorts, another use is place-it in series and it will only leak some current when polarity is inverted.
    I placed in parallel because if user does not connect it properly it will have a nasty surprise, and the idea is that he will imidiatly notice, please recommend this or other method.
    Calculations of the values are not done yet so please ignore the componentes value.
    The input voltage at J3 and J4 will be a switching power suppy with short circuit protection, and I will add a fast fuse to the design.
  2. BobTPH

    Active Member

    Jun 5, 2013
    I don't understand why you don't want to put the diodes in series to simply block reversed input voltage, but if you insist, put the reverse voltage protection diodes after the resistor, then there is not a short.

    Also, you cannot parallel the indicator LED and the opto-isolator that way. Use a separate resistor (and separate protection diode) for each.

    edmundopt likes this.
  3. edmundopt

    Thread Starter Member

    May 4, 2011
    found two application notes from Avago, and just copy them, as you mentioned the reverse protection diode goes after the resistors. Led also changes to serial conection.
    thks for the reply