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Impossible Circuit - Any Ideas?

Discussion in 'Electronic Design' started by aaronej, Nov 22, 2006.

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  1. aaronej

    aaronej Guest

    I saw this the other day and I was mystified. The circuit has a green
    and red light bulb, and a green and red switch. Initially, the red
    switch turns the red bulb on and the green switch turns the green
    switch on. When both switches are on, both bulbs are on

    Here's the catch:
    When you switch the Red and the Green Light bulb, the red switch still
    controls the red light bulb and the green switch still controls the
    green light bulb.

    Can anyone explain or diagram this?
  2. Phil Allison

    Phil Allison Guest

    ** Groper alert !!

    ** The supply is AC and the bulbs have diodes fitted inside them, wired in
    series with the filament.

    The switches also have diodes in series with them.

    So, the lamp sockets are simply wired in parallel and it make no difference
    which is used.

    ......... Phil
  3. Jamie

    Jamie Guest

    sure, they had diodes on the switchs and bulbs.
  4. Iwo Mergler

    Iwo Mergler Guest

    There is also an alternative series circuit:

    | | | | | |
    | +-|>|-+ +-|<|-+ |
    o |
    AC ~ |
    o |
    | +-|>|-+ +-|<|-+ |
    | | | | | |

    Again the diodes are inside the bulb socket.
    You can swap the bulbs with baffling results
    and it won't work with one bulb removed. ;-)

    It's a fun circuit when built on clear perspex.

    Kind regards,

  5. Mike

    Mike Guest

    It's a "magic trick" ... sounds like ... US Patent No 5790013 ?

  6. Mike Monett

    Mike Monett Guest

    Mike, how on earth did you find that patent?

    There's no way I could have searched the patent database and come up with
    that number.

    You should patent your search method:)


    Mike Monett

    Antiviral, Antibacterial Silver Solution:
    SPICE Analysis of Crystal Oscillators:
    Noise-Rejecting Wideband Sampler:
  7. Donald

    Donald Guest

    This is so silly.

    A patent !!! for this !!???

    No wonder many say that the US Patnet office is in dire need of house
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