Bonds shall not be issued, except special assessment bonds, bonds for the portion of the cost of local improvements to be paid by the city at large, not to exceed 40% of the cost of the improvements, bonds for capital improvements in the annual budget as provided in section 18 of this chapter, emergency bonds, and bonds which the council is authorized by specific statute to issue without vote of the electors, unless approved by a majority of the electors voting thereon at any regular or special city election. The election shall be conducted in accordance with the general laws governing the conduct of elections.