switching help

Discussion in 'General Electronics Chat' started by hamopp, Feb 11, 2010.

  1. hamopp

    Thread Starter Active Member

    May 13, 2009
    68
    1
    Hi
    Anyone able to help me with this :eek:
    Can i use 4066 switch's to do this ?
    I must point out that the 8volt supply for the Tx and Rx units draws about 700mA, so this has to pass 8v@700mA through the 4066's, also there is a .6v drop through both D6 and D7

    Please look at the pdf file

    Thanking you
    Howard
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    4066 are not capable of switching 700ma.
     
  3. hamopp

    Thread Starter Active Member

    May 13, 2009
    68
    1
    Hi

    Is there any other switch ic that has 4 switch's that can do this ??

    Howard
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    IC, no. MOSFETs can.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I notice that 1N4148 diodes are shown in the schematic. If you try to run 700mA through them, they will disappear in a bright flash. :eek: Instead, use Schottky diodes, like 1N5817 for a low Vf.

    There are no reverse-EMF protection diodes on the relay coils. That will wreak havoc on the logic board, besides generating broadband RF interference when the current through the coils is discontinued.
     
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