1Hz from 60 hz main

Discussion in 'General Electronics Chat' started by arthur92710, Feb 12, 2008.

  1. arthur92710

    Thread Starter Active Member

    Jun 25, 2007
    307
    1
    I have a circuit that takes 60Hz from the mains and transforms it into 1hz. Can someone look at it and verify that it outputs 1 hz. Im not sure of the second counter. Thanks

    [​IMG]
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
  3. arthur92710

    Thread Starter Active Member

    Jun 25, 2007
    307
    1
    Thanks I will use your circuit instead. It has less parts and look simpler.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    Here's another option, with the added bonus that the 555 runs at close to 60Hz if you have a power failure. You would need a backup battery for vcc, of course.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I rather like Ron H's suggestion better. There are other options than to use two 4017 IC's.

    The schematic you originally posted could be quite brutal on the Schmitt-input U1, as there are no provisions to protect it from voltage swings above/below Vdd/Vss.
     
  6. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Just in case anyone actually wants to us the original schematic, it should be noted that the bridge rectifier o/p is 120Hz, not 60Hz. The o/p is therefore 2Hz.
     
  7. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    Actually, the way the bridge is connected, it may be just a smoke generator, as it shorts out the transformer on alternate half cycles of power.
    If the bridge connection is corrected, the Schmitt may be destroyed, as SgtWookie pointed out.
    The 7805 is powered off the output of the Schmitt.:eek:
    If the 7805 input is moved to the bridge output, then the Schmitt won't switch.
    100nF is way too small for the rectifier filter.
    I didn't check the logic.
     
  8. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Ah, yes! The old rotated bridge error. :cool: I am in great debt to the makers of Eagle Light for having the foresight to add "~" and "+" and "-" to bridge rectifier symbols!
     
  9. arthur92710

    Thread Starter Active Member

    Jun 25, 2007
    307
    1
    what do you mean by 120hz? It is 120v and 60 hz so what do you mean?

    Oh! the bridge makes the 60hz into 120hz because the wave goes form ac to dc
    like in the pic
    [​IMG]
     
  10. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Actually this circuit does not work!! The bridge rectifier is connected in a wrong way. Also, the input of the 7805 is connected after the schmitt trigger!!!!!
     
  11. arthur92710

    Thread Starter Active Member

    Jun 25, 2007
    307
    1
    I have a question about the 4017
    Do the unused outputs have to be grounded?
    *EDIT* No they dont
     
  12. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    No, you dont need to ground the unused outputs. If you ground them and one of them goes high you will probably blow the IC
     
  13. arthur92710

    Thread Starter Active Member

    Jun 25, 2007
    307
    1
    :eek: dont want that!
     
Loading...