Disposable batteries are also known as primary cells. They are intended for a one time use only, to be used until the chemical changes used to induce its electrical current supply have been finished. Their common usages include smaller, more portable devices that have either a low current drain or are used away from any alternative power source.

Rechargeable batteries, also known as secondary cells, have a longer usage life since they can be recharged after their power has been drained. You can do so by applying an externally supplied electrical current. This causes a reversal in the chemical changes that occur during the battery’s use. These devices used to do this are commonly known as rechargers or chargers.

The ‘wet cell,’ or lead-acid, battery is the oldest form of the rechargeable battery that is still in today’s use. This battery contains a liquid found in an unsealed container that requires the battery to be kept in an upright position. The area in which it is used must be well-ventilated so as not to cause the ventilated, hydrogen gas to display its explosive qualities.

The lead-acid battery is quite heavy, although its cost to manufacture is low and the high surge content levels allow it to be a commonly used battery in places where its weight and handling ease are not of any concern.

The most common form of a lead-acid battery is the car battery.

A gel battery is known to be an expensive lead-acid battery type, containing a semi-solid electrolyte that is used to prevent spillage.

The portable types are considered to be ‘dry cells.’ They are sealed units that are useful in appliances such as cell phones and laptop computers. These types of cells also include, nickel-cadmium or NiCd, nickel metal hydride or NiMH, and lithium-ion or Li-Ion, listed in the order of their increasing power density and also their cost.

Both disposable batteries and rechargeable batteries come in various standard sizes. This is so they can easily be used in a wider amount of appliances. The most commonly known types of batteries are the A-series, including A, AA, AAA, and AAAA. Also known are B, C, D, F, G, J, and N. Other variants include 3R12, 4R25, PP3, PP9, and the 996 and PC926 that are used in lanterns. There are many, many more less common battery types, and their usages vary greatly.

Some people find that their baby monitor can be interrupted by cell phones, mobile phones, computer networks and even your neighbors baby monitors. Be aware of any potential interruptions before you put the monitor into official use. Also, make sure you get a monitor with a receiving unit that emits a tone when the battery is going low so you won’t be caught with a dead battery.

Another consideration before purchasing a baby monitor is the range the monitors have. If you have a more regular sized home say 1,800 you probably won’t have any problem with a conventional baby monitor. If you live in a home that has square footage of 4,000 or more, or if you live in a multi level home you may need a specific type of unit.

There are baby monitors available that actually feature what is called a “sensor pad”. The pad is placed underneath the crib sheet and picks up any movement the baby may make. Some physicians recommend these types of monitors for premature babies.

A cheap alternative to dedicated barcode generators are so called barcode fonts. However, the quality a barcode created with such a font will usually not conform to the respective standards.

Depending on the application the use of dedicated, barcode enabled, label printing software may be advised. For example, such software can be used to print sequential barcodes (for serial numbers) or print logos or product images next to the actual barcode.

Barcode Scanner

Barcode Scanners, also known as barcode readers exist in various forms: The most common type are laser scanners. Here a moving laser beam scans the code which results in fast and error free reading. A cheap alternative to laser scanners are CCD scanners that feature a row of light emitting diodes and photo detectors. The earliest type of barcode reader where so called barcode wands, also known a magic wands. Here a single light emitting diode (LED) and a single photo detector are used to detect the typical black and white pattern of a barcode. While laser and CCD barcode scanners scan a barcode as a whole the barcode wand has to be swiped across the code to read it.

Barcode Printers

Barcode printers are used to print the barcode on self adhesive labels. Today most barcode label printers work in either thermo direct or thermo transfer mode. Using the thermo direct principle the print head applies heat to selected parts of the label which then turn dark. This is the same principle as is used with older fax machines. Thermo direct labels are sensitive to light and should not be used if they have to last longer than a few days or weeks. Typical applications are address labels which only have to last a few days.

With thermo transfer printers a heat sensitive ribbon (thermo transfer ribbon) sits between the print head and the label. As heat is applied to the ribbon, ink transfers (hence the name) from the ribbon to the label. Labels that were printed with thermo transfer are very durable. However, besides the actual label the transfer ribbon is another consumable which will increase the printing cost.