4 ms·

They’ll have different resistance. Sometimes it matters, sometimes it doesn’t.

• dotancohen 5y ago
  I came to post this. The offset ears on the bulb base are used to specify either a dual-filament bulb, such as tail lamps and brake lamps combined, or high-resistance, low-wattage parking lamps that are designed to not run down the battery while the alternator is not charging.
  • WalterBright 5y ago
    That makes sense. The cheap bulbs I bought were just slightly dimmer. So they must have had more resistance. But heck, even a parking light will flatten the battery if left overnight.
    • dotancohen 5y ago
      > But heck, even a parking light will flatten the battery if left overnight. Nominal modern car batteries are about 12.6 volts. I wonder if the high-resistance bulbs will completely dim once the voltage drops to a specific threshold, say around 12.0 volts. If they do, then they should leave just enough charge to crank, as most starter motors can safely crank over with about eleven and a half volts (and all the way up to over 14 volts). That might be an interesting experiment to test.