For the purpose of purchasing voting machines, the county board of any county having more than 500,000 inhabitants and in which county there has been a favorable vote on the proposition of adopting voting machines as provided by Article 24 of “The Election Code”, as amended, may, by resolution, incur an indebtedness and issue bonds therefor in the aggregate of not more than $500,000 in addition to all bonded indebtedness authorized for that purpose prior to July 1, 1949.
     However, no resolution providing for the issuance of bonds as authorized by Sections 6-5001 through 6-5005 shall be effective until it has been submitted to referendum of the electors of that county. The board shall certify the resolution and the proposition to the proper election officials who shall submit the proposition at an election in accordance with the general election law. In addition to the requirements of the general election law, notice of the referendum shall also set forth the substance of the resolution. If a majority of those voting upon the proposition at such referendum vote in favor of issuing such bonds, then the resolution shall immediately become effective.