Laptops (and computers in general) run on 12V DC and 5V DC (and more recently also 3.3V DC) internally. Modern laptop chargers tend to put out around 20V DC to charge the battery and stepped down by power management circuits. Not sure if it was already 20V in '98 or if laptops were still using 12V DC to charge the NiCads, I seem to remember car chargers that plugged the laptop directly into the cigarette lighter.