When to use JSON.stringify() in an ajax call [duplicate]

My knowledge of ajax and JSON is limited, but I know that using JSON.stringify in an ajax call can sometimes be useful. I have an ajax call below that works fine, while the one below it with the stringify method that does not work. I am wondering if I am using .stringify correctly, and if not, when should I use JSON.stringify in ajax, if ever. I am using MVS with a model, view, and controller.

This is how I usually do ajax calls, and how i build the url portion.

    function AddEquipment(id, name, type, description, email) {
        $.ajax({
            url: '@Url.Action("AddEquipment", "Home")' + '/?id=' + id +
                "&name=" + name + "&type=" + type + "&description=" +
                description + "&email=" + email,
            type: "GET",
            cache: false,
            datatype: "JSON",
            success: function(result) {
                //do stuff
            }
        });
    }

Below I have tried using JSON.stringify instead of building the entire url manually, and it does not work.

    function AddEquipment(id, name, type, description, email) {
        $.ajax({
            url: '@Url.Action("AddEquipment", "Home")',
            type: "GET",
            cache: false,
            datatype: "JSON",
            data: JSON.stringify({
                "id": id,
                "name": name,
                "type": type,
                "description": description,
                "email": email
            }),
            success: function(result) {
                //do stuff
            }
        });
    }

the controller method this goes with accepts id as an int, while everything else is a string. I have used JSON.stringify before with mixed variables (ints, bools, strings) without an issue.

Any helpful information is greatly appreciated,

Thanks!