Some items now come with the batteries already installed. A small hole in the battery compartment allows you to pull out a little tab of non-conductive material from the outside. How long has this been around?
I’ve only noticed this recently - most recently on a promotional Guinness bottle opener that exclaims “brilliant!” when you open a beer. Before that, only on an el-cheapo travel clock I bought in Singapore. Both items had watch-sized batteries. The tab allows stuff to be shipped ready to work without any fear that the battery will discharge or spoil the device in transit or storage.
How long has this been around? Is it confined to small, light batteries?
These little, throwaway/very cheap battery-operated devices containing sounders and/or flashing LEDs are very much more common than they were a few years ago; I think it has pretty much always been the case that most small electronic items requiring non-standard cells (that is, not AA or AAA etc) have been supplied with batteries included.
It used to be the case that the buyer would install the cells at home, but I would imagine they are supplied pre-installed (with the little insulator tab) for a number of reasons, including:
-Easier to QC on the production line, inserting the tab after the device is confirmed working.
-The devices may not be easy to open, or all that durable - pre-installing the cells means the end user is less likely to break the thing before first use.
-The cells, when supplied with the device, but not preinstalled, require packaging and present a slightly elevated risk of accidental ingestion by children etc, or they can be misplaced on the shelf.
-Many of these items are designed to be used as promotional handouts (happy meal toys, for example) - the staff giving them out don’t want to be fussing around with them and the customers expect them to just work straight away.
Some of the small batteries are zinc-air batteries. Oxygen is one of the two reagents in the cell’s operation. The tab covers small holes in the case that let air flow in, keeping the battery charged.
Others use a “soft” power on/off button that never completely turns off the device. The tab can be removed to complete the circuit so that the batteries aren’t totally drained before you take the device out of the packaging - the Sega Dreamcast’s VMU stands out in my mind as an example of this.