Welcome to CPF, chef! :thumbsup:
Now Im sure theres already some info on here but....
Yeah, that's a pretty good guess.
To get you started though, NiMH cells are rechargeable (secondary) nickel based cells that pretty much have replaced NiCd cells and are superior in most ways (but not all). They have a "nominal" (meaning under a typical load) voltage of 1.20 Volts. This "nominal" bit is of importance when comparing to alkaline cells, which while rated at "1.5 Volts", often under even a medium load have the same voltage. Under high current loads, the NiMH cell will almost always maintain a higher voltage.
"Primary" (meaning non rechargeable) lithium cells come in a variety of chemistries in which the voltage can range from 1.5 to 3.7 volts. In the AAA and AA size, the most common are the 1.5 Volt variety, such as the Energizer L91, L92, EA91, and EA92 cells. The Energizer primary AAA and AA cells mentioned, have an open circuit voltage (OC) which is a bit higher than alkaline cells, generally around 1.7 Volts. This voltage advantage generally holds up under load as well, when compared to alkaline cells, and is sometimes a problem with some voltage sensitive devices, particularly incandescent bulbs, when more than one cell is used, as the voltage difference grows larger, the more cells that are used in a series application.
You didn't mention them, but there are also lithium ion cells (Li-Ion) which are a secondary (rechargeable) cell. These are
very different than lithium primary cells (eg. they contain no lithium, only lithium within the chemical compounds used in the cell's components), and should not be confused, and much more care should be taken when using and maintaining these chemistry cells. In addition, there are many different chemistries of Li-Ion cells, 3 or 4 are common on these Forums (LiCo, LiMn, LiFe being the three most common, and also a nickel cobalt chemistry). The voltages of these cells range from 3.2-4.35 Volts/cell.
Hope this helps a bit. A good source to learn more about secondary (rechargeable) cells, is at
Battery University. Also the
stickies and
whatnot at the top of this forum can provide you with additional information here on CPF.
Dave
EDIT: Oh, and yeah, the mods and administrators are pretty slick here, as well.:naughty: