How to set character limit on the_content() and the_excerpt() in wordpress

//=====Text limit in pages, categories, home page
add_filter("the_content", "break_text");
function break_text($text){
    $length = 500;
    if(strlen($text)<$length+10) return $text;//don't cut if too short

    $break_pos = strpos($text, ' ', $length);//find next space after desired length
    $visible = substr($text, 0, $break_pos);
    return balanceTags($visible) . "...";
}

source: http://stackoverflow.com