In different ways at different times. I am assuming you are referring to the Republic of Venice (as opposed to, for example, the City during the brief French Occupation, or under the Austrian Empire) in which case the older answers below might interest you, although there is always more that can be said on the sometimes absurd intricacies of Venetian government:
The early centuries of the Venetian government system, which would imprint a certain institutional predisposition into the Republic's collective memory.
The significant 13th century changes to the Republic's political system
A closer look at the evolution of the election of the Doge of Venice, which might be what you're referring to with "Electoral System"