Terms Related to Batteries, Power Supplies and Chargers
AC / ALTERNATING CURRENT - An electric current that reverses direction continuously at regular intervals, most often at a frequency of 50 or 60 Hz. AC appears as a sinusoidal trace on an oscilloscope screen.
AGENCY APPROVAL - Underwriters' Laboratory (UL), Canadian Standards Association (CSA) and TÜV TÜVRheinland Group are safety agencies that test specifications such as component spacing, HI-pot insulation, leakage currents, circuit board flammability and temperature ratings.
AMBIENT TEMPERATURE - The still air temperature in the immediate vicinity of a power supply, measured at a minimum of 4 inches from the supply.
ANSI - American National Standards Institute. An industry body that publishes standards, such as standards developed by the IEEE
AMPERE (Amp) - The basic unit of electric current flowing in a system with a resistance of one Ohm (ω).The algebraic symbol for ampere is I.
AMPERE-HOURS - Measure of cell capacity. Number of hours a cell can generate a current of 1 Amp.
ANODE - The electrode in a cell/battery where oxidation takes place. During discharge, the negative electrode of the cell/battery is the anode. During charge, the positive electrode is the anode.
BATTERY - Two or more cells interconnected in an appropriate series/parallel arrangement to provide required operating voltage and current levels. Under common usage, "battery" is often applied to single cells.
BATTERY BACKUP - A power supply system in which, if the AC line fails, a battery will provide input energy to keep the DC outputs from failing.
CAPACITY - The total number of ampere-hours that can be withdrawn from a fully charged cell/battery under specified discharge conditions.
CATHODE - The electrode in a cell/battery where reduction takes place. During discharge, the positive electrode of the cell/battery is the cathode. During charge in a rechargeable battery, the negative electrode is the cathode.
CE - The Mark is a mandatory mark indicating that a product may be legally offered for sale in any country within the European Union. It symbolizes the compliance of the product with all essential requirements relating to safety, public health, consumer protection.
CELL - The basic electrochemical unit used to generate or store electrical energy. Two or more cells interconnected in an appropriate series/parallel arrangement is a battery. Under common usage, "battery" is often applied to single cells.
C RATE - Discharge or charge current, in amperes, expressed in multiples of the rated capacity. For example, C/10 discharge current for a cell rated at 1.2 Ah is: 1.2 Ah/10, or 120 mA.
CYCLE LIFE - The number of cycles under specified conditions that are available from a rechargeable battery before it fails to meet specified performance criteria.
CONSTANT CURRENT POWER SUPPLY - A power supply that regulates its output current for changes in line, load, ambient temperature and time.
CONSTANT VOLTAGE POWER SUPPLY - A power supply that regulates its output voltage for changes in line, load, ambient temperature and time.
CONVERTER - An electrical circuit which accepts a DC input and generates a DC output of a different voltage, usually achieved by high frequency switching action employing inductive and capacitive filter elements.
CURRENT - The flow of electricity expressed in amperes. Current refers to the quantity or intensity of electricity flow, whereas voltage refers to the pressure or force causing the electrical flow.
CSA - Canadian Standards Association, a Canadian not-for-profit organization that develops standards, evaluates the safety of electrical equipment, and provides training and education.
DC - Direct Current. Electrical current that flows in one direction.
DESIGNED LIFE - The expected lifetime of a power supply during which it will operate to its published specifications.
DOC - Declaration of Conformity, in which a manufacturer declares that a product conforms to specific standard, such as those issued by the European Community.
EFFICIENCY - The ratio of total output power to input power, expressed as a percentage. This is normally specified at full load and nominal input voltage.
ELECTRICITY - The flow of electrons through conductive materials and devices.
ELECTRODE - The area where an electrochemical processes take place.
ELECTROLYTE - A substance containing free ions that behaves as an electrically conductive medium. In batteries, an electrolyte is the medium that provides the ion transport mechanism between the positive and negative electrodes of a cell/battery.
EMC - Electromagnetic Compatibility. The requirement for electromagnetic emissions and susceptibility dictated by the physical environment and regulatory governing bodies in whose jurisdiction a piece of equipment is operated.
EMI - Electromagnetic Interference. EMI is unwanted electrical noise present on a power line.
ENERGY - The output capability of a cell/battery, usually expressed in watt-hours. Mainly used for rechargeable batteries.
ENERGY DENSITY - The ratio of the energy available from a cell/battery to its volume (Wh/L) or weight (Wh/kg). Mainly used for rechargeable batteries.
FCC - Federal Communications Commission.
FCC CERTIFIED - A statement of compliance with US FCC class "B" limits for radio frequency emission, which is issued by the FCC and accompanied by a FCC "registration" or "ID" number. Certified equipment must be marked with the ID number.
GROUND - Electrical ground in an AC power system is a wire that is connected to the earth (hence the name "ground") It is intended to protect users of electrical equipment from shock hazards.
IEC - International Electro-Technical Commission. An international organization that writes standards for safety for electrical and other equipment. Many IEC standards were adopted from the German VDE, which was the main historical standards-writing body in Europe.
INVERTER - A power supply which produces an AC output, usually from a DC input.
MEMORY EFFECT - A phenomenon in which a cell/battery operated in successive cycles to the same, but less than full, depth of discharge temporarily loses the rest of its capacity at normal voltage.
MTBF - Mean Time Between Failure. A measurement of the relative reliability of a power supply based upon actual operating data or calculated according to MIL-HDBK-217.
NSN - National Stock Number. Assigned to cells and batteries purchased by the Department of Defense and other military/government agencies. Numbers format: XXXX-XX-XXX-XXXX
OFF-LINE - A power supply that receives its input power from the AC line, without using a 50/60 Hz power transformer prior to rectification and filtering, hence the term "off line" power supply.
OHM (ω) - A unit of electrical resistance (volts/ampere). The algebraic symbol for ohm is R.
OPERATING RANGE - The minimum and maximum input voltage limits within which a power supply will operate to specifications.
OPERATING TEMPERATURE - The range of ambient temperatures within which a power supply can be safely operated.
OUTPUT CURRENT - The maximum current which can be continuously drawn from the output of a power supply.
OUTPUT IMPEDANCE - The ratio of change in output voltage to change in load current.
OUTPUT POWER - The specified level of power of which a power supply is capable. Typically, power supplies have a continuous rating and a peak rating. These are usually a function of the ambient temperature.
OVERCURRENT PROTECTION - A circuit that protects the power supply and computer from excessive current, including short-circuit current.
OVERVOLTAGE PROTECTION - A power supply feature that shuts down the supply, or clamps the output, when its voltage exceeds a preset level.
PARALLEL CONFIGURATION - The connection of cells/batteries where all the like terminals are connected together resulting in increased capacity.
PCM - Protection Circuit Module
PEAK CURRENT - The maximum amount of current that a source can output for brief periods of time.
POWER SUPPLY - A source for the power needed for active electronic circuitry. Can consist of one or more batteries, or an electronic circuit which converts AC line voltage to the type of power required by a particular device.
PTC - A device that protects the cell/battery from external short circuits while allowing the cell/battery to continue functioning after a short circuit is removed.
PRIMARY BATTERY - A non-rechargeable battery.
REVERSE VOLTAGE PROTECTION - A protection circuit that prevents the power supply from being damaged in the event that a reverse voltage is applied at the input or output terminals.
RFI - Radio Frequency Interference. This is electrical noise present in communications or computing equipment that results from some parts of the equipment or attached wiring acting as a radio antenna. Under certain conditions the amplitude of this noise may be large enough to disrupt communications or cause computing errors.
SECONDARY BATTERY - A rechargeable battery.
SELF DISCHARGE - Normal loss of capacity of a cell/battery during storage due to internal chemical action.
SERIES CONFIGURATION - Connection of cells/batteries where the positive terminal of the first is connected to the negative terminal of the second, and so on. This results in increased voltage.
SHORT CIRCUIT PROTECTION - In the event that the output is shorted, this circuit will protect the power supply by limiting the amount of current flowing through the short circuit.
TEMPERATURE DERATING - The reduction in output power due to an increase in ambient temperature.
TEMPERATURE RANGE (Operating) - The specified ambient temperature range over which it is safe to operate the power supply.
TEMPERATURE RANGE (Storage) - The specified ambient temperature range in which the power supply can be stored without risk of damage.
THERMAL PROTECTION - A power supply protection circuit which shuts the power supply down in the event of unacceptably high internal temperatures.
TRICKLE CHARGE - A charge at a low rate of current to keep a cell or battery fully charged. Not recommended for lithium ion or lithium polymer batteries.
TÜV - TÜV is a safety-testing laboratory with headquarters in Germany. TÜV can test products for compliance with IEC (International Electrotechnical Commission) or VDE (German Association for Electrical, Electronic and Information Technologies) requirements.
UL - Underwriters Laboratories, Inc. A private organization that develops standards and test procedures for materials, components, assemblies, tools, equipment and procedures, chiefly dealing with product safety and utility. UL was originally founded as a result of the need for insurance companies to help consumers choose safe electrical and safety equipment. UL evaluates equipment submitted to them by manufacturers using standards written by UL for the equipment category. Equipment that meets the safety requirements is either UL Listed or UL recognized. Many insurance companies and local electrical codes in the U.S. require that installed electrical equipment be UL Listed.
UL APPROVED - This is a widely used term that is technically not correct. The correct terms are UL LISTED or UL RECOGNIZED.
UL LISTED - UL grants this form of approval to equipment that will be user installed or operated and that is found to meet the safety requirements of the applicable UL standards. If a product is UL Listed, then it must be marked with the UL symbol.
UL RECOGNIZED - This is a form of formal approval granted by UL to devices that are not used as free standing equipment on their own, but are to be installed into some other system by a manufacturer, electrician, or possibly by an end-user.
VOLTAGE - The unit of measurement of electric potential. Voltage is the difference in electrical energy between two points.
VOLT - The unit of measurement defining the force needed to send one Ampere of current through a system with a defined amount of resistance. The algebraic symbol is V. Amps x Resistance = Volts (I x R = V) Note: the voltage of batteries is quoted as "nominal" because it varies during the life of the battery and the amount and rate of current being taken from the battery.
WATT - The unit of measurement for electrical power being generated or used. The algebraic symbol of a watt is "W". Volts x Amps = Watts ( V x A = W )
WATT-HOUR (Wh) - The unit for measuring electrical capacity or the number of watts per hour of the battery. Watts x hours = Watt hours (W x h = Wh) or Volts x Amps X hours = Watt hours (V x A h = Wh)
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