diode with fuse circuit protector

Discussion in 'Homework Help' started by fran1942, Jul 28, 2010.

  1. fran1942

    Thread Starter Member

    Jul 26, 2010
    hello, I am having a little trouble understanding how this works:

    my attached (appalling sketch) is of a circuit protection circuit to prevent incorrect polarities of power source being connected to a load.
    There is a fuse which is then connected both to the load and to a diode.

    Can someone please outline to me how this actually functions.

    Thanks kindly for any help.
  2. c_omalley2002


    Mar 18, 2010
    When the power supply is connected correctly, the diode is reverse biased. No current will flow through it. If the power supply is connected backwards, the diode will be forward biased. This will cause current to flow through the diode, bypassing the load. This creates a short circuit, drawing maximum current and blowing the fuse. The fuse is there to protect the power supply from damage.

    Keep in mind the diode and fuse must be chosen based on the voltage, current, and type of load