Unless otherwise provided by the articles of incorporation or bylaws, any action required by the Business Corporation Act to be taken at a meeting of the directors of a corporation, or any action which may be taken at a meeting of the directors or of a committee, may be taken without a meeting if a consent in writing, setting forth the action so taken, shall be signed by all of the directors, or all of the members of the committee, as the case may be. The consent shall have the same effect as a unanimous vote.