71-413: The Motorola MicroTAC is a cellular phone first manufactured as an analog version in 1989. GSM -compatible and TDMA / Dual-Mode versions were introduced in 1994. The MicroTAC introduced a new " flip " design, where the "mouthpiece" folded over the keypad, although on later production the "mouthpiece" was actually located in the base of the phone, along with the ringer. This set the standard and became
142-475: A dark orange dot-matrix LED display (only 9800X models had a true red display) and additional menu features. Lites, Ultra-Lites, Lite IIs, Lite XLs, Elites, and Alphas were all available as VIP phones. Analog signal An analog signal ( American English ) or analogue signal ( British and Commonwealth English ) is any continuous-time signal representing some other quantity, i.e., analogous to another quantity. For example, in an analog audio signal ,
213-405: A freshly charged AA NiMH cell in good condition is about 1.4 volts. Complete discharge of multi-cell packs can cause reverse polarity in one or more cells, which can permanently damage them. This situation can occur in the common arrangement of four AA cells in series, where one cell completely discharges before the others due to small differences in capacity among the cells. When this happens,
284-453: A fully charged state. Some chargers do this after the charge cycle, to offset natural self-discharge. A similar approach is suggested by Energizer, which indicates that self-catalysis can recombine gas formed at the electrodes for charge rates up to C/10. This leads to cell heating. The company recommends C /30 or C /40 for indefinite applications where long life is important. This is the approach taken in emergency lighting applications, where
355-470: A higher specific energy than nickel–metal hydride batteries, but they were originally significantly more expensive. The cost of lithium batteries fell drastically during the 2010s and many small consumer devices now have non-consumer-replaceable lithium batteries as a result. Lithium batteries produce a higher voltage (3.2–3.7 V nominal), and are thus not a drop-in replacement for AA (alkaline or NiMh) batteries without circuitry to reduce voltage. Although
426-534: A popular improvement of the NiMH battery and founded Ovonic Battery Company in 1982. General Motors purchased Ovonics' patent in 1994. By the late 1990s, NiMH batteries were being used successfully in many fully electric vehicles, such as the General Motors EV1 and Dodge Caravan EPIC minivan. This generation of electric cars, although successful, was abruptly pulled off the market. In October 2000,
497-539: A protection layer), alkaline treatment of negative electrode (causing reduction of leach-out of Mn and Al), addition of LiOH and NaOH into electrolyte (causing reduction in electrolyte corrosion capabilities), and addition of Al 2 (SO 4 ) 3 into electrolyte (causing reduction in MH alloy corrosion). Most of these improvements have no or negligible effect on cost; some increase cost modestly. NiMH cells are often used in digital cameras and other high-drain devices, where over
568-634: A rate of around 1× C (full discharge in 1 hour), it does not differ significantly from the nominal capacity. NiMH batteries nominally operate at 1.2 V per cell, somewhat lower than conventional 1.5 V cells, but can operate many devices designed for that voltage . NiMH batteries were frequently used in prior-generation electric and hybrid-electric vehicles; as of 2020 they have been superseded almost entirely by lithium-ion batteries in all-electric and plug-in hybrid vehicles, but they remain in use in some hybrid vehicles (2020 Toyota Highlander, for example). Prior all-electric plug-in vehicles included
639-514: A red dot matrix LED display. 1994 saw the introduction of the MicroTAC Elite and the "International" series, the then smallest and light-weight model available at the time. It weighed in at a mere 3.9 ounces (110 g) with the slim battery. The Elite was a function of NAMPS technology from 1993. The Elite was also produced in a rare MicroTAC Elite VIP ( pictured ), which had a black housing, gold lettering, and an orange LED display, over
710-504: A single lithium cell will typically provide ideal power to replace 3 NiMH cells, the form factor means that the device still needs modification. NiMH batteries can easily be made smaller and lighter than lead-acid batteries and have completely replaced them in small devices. However, lead-acid batteries can deliver huge current at low cost, making lead-acid batteries more suitable for starter motors in combustion vehicles. As of 2005 , nickel–metal hydride batteries constituted three percent of
781-533: A subsidiary of Daimler AG . The batteries' specific energy reached 50 W·h/kg (180 kJ/kg), specific power up to 1000 W/kg and a life of 500 charge cycles (at 100% depth of discharge ). Patent applications were filed in European countries (priority: Switzerland), the United States, and Japan. The patents transferred to Daimler-Benz. Interest grew in the 1970s with the commercialisation of
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#1732791484035852-643: A substitute for similarly shaped non-rechargeable alkaline batteries , as they feature a slightly lower but generally compatible cell voltage and are less prone to leaking . Work on NiMH batteries began at the Battelle -Geneva Research Center following the technology's invention in 1967. It was based on sintered Ti 2 Ni+TiNi+x alloys and NiOOH electrodes. Development was sponsored over nearly two decades by Daimler-Benz and by Volkswagen AG within Deutsche Automobilgesellschaft, now
923-530: A successful battery based on this approach (using a mixture of La 0.8 Nd 0.2 Ni 2.5 Co 2.4 Si 0.1 ), which kept 84% of its charge capacity after 4000 charge-discharge cycles. More economically viable alloys using mischmetal instead of lanthanum were soon developed. Modern NiMH cells were based on this design. The first consumer-grade NiMH cells became commercially available in 1989. In 1998, Stanford Ovshinsky at Ovonic Battery Co. , which had been working on MH-NiOOH batteries since mid-1980, improved
994-454: A sulfonated polyolefin separator, an improvement over the hydrophilic polyolefin based on ethylene vinyl alcohol . Low-self-discharge cells have somewhat lower capacity than otherwise equivalent NiMH cells because of the larger volume of the separator. The highest-capacity low-self-discharge AA cells have 2500 mAh capacity, compared to 2700 mAh for high-capacity AA NiMH cells. Common methods to improve self-discharge include: use of
1065-800: A sulfonated separator (causing removal of N-containing compounds), use of an acrylic acid grafted PP separator (causing reduction in Al- and Mn-debris formation in separator), removal of Co and Mn in A 2 B 7 MH alloy, (causing reduction in debris formation in separator), increase of the amount of electrolyte (causing reduction in the hydrogen diffusion in electrolyte), removal of Cu-containing components (causing reduction in micro-short), PTFE coating on positive electrode (causing suppression of reaction between NiOOH and H 2 ), CMC solution dipping (causing suppression of oxygen evolution), micro-encapsulation of Cu on MH alloy (causing decrease in H 2 released from MH alloy), Ni–B alloy coating on MH alloy (causing formation of
1136-467: A timer. Most manufacturers claim that overcharging is safe at very low currents, below 0.1 C ( C /10) (where C is the current equivalent to the capacity of the battery divided by one hour). The Panasonic NiMH charging manual warns that overcharging for long enough can damage a battery and suggests limiting the total charging time to 10–20 hours. Duracell further suggests that a trickle charge at C /300 can be used for batteries that must be kept in
1207-467: Is 5–20% on the first day and stabilizes around 0.5–4% per day at room temperature . But at 45 °C (113 °F) it is approximately three times as high. The low–self-discharge nickel–metal hydride battery ( LSD NiMH ) has a significantly lower rate of self-discharge. The innovation was introduced in 2005 by Sanyo , branded Eneloop . By using improvements to electrode separator, positive electrode, and other components, manufacturers claim
1278-473: Is AB 5 , where A is a rare-earth mixture of lanthanum , cerium , neodymium , praseodymium , and B is nickel , cobalt , manganese , or aluminium . Some cells use higher-capacity negative electrode materials based on AB 2 compounds, where A is titanium or vanadium , and B is zirconium or nickel, modified with chromium , cobalt, iron , or manganese . NiMH cells have an alkaline electrolyte , usually potassium hydroxide . The positive electrode
1349-504: Is a type of rechargeable battery . The chemical reaction at the positive electrode is similar to that of the nickel–cadmium cell (NiCd), with both using nickel oxide hydroxide (NiOOH). However, the negative electrodes use a hydrogen-absorbing alloy instead of cadmium . NiMH batteries can have two to three times the capacity of NiCd batteries of the same size, with significantly higher energy density , although only about half that of lithium-ion batteries . They are typically used as
1420-522: Is converted to an analog signal by a transducer . For example, sound striking the diaphragm of a microphone induces corresponding fluctuations in the current produced by a coil in an electromagnetic microphone or the voltage produced by a condenser microphone . The voltage or the current is said to be an analog of the sound. An analog signal is subject to electronic noise and distortion introduced by communication channels , recording and signal processing operations, which can progressively degrade
1491-471: Is employed, when the cells vary in temperature. This is because capacity significantly declines as the cells are cooled. This results in a lower voltage under load of the colder cells. Historically, NiMH cells have had a somewhat higher self-discharge rate (equivalent to internal leakage) than NiCd cells. The self-discharge rate varies greatly with temperature, where lower storage temperature leads to slower discharge and longer battery life. The self-discharge
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#17327914840351562-679: Is irreversible as there is no reliable method to distinguish the noise from the signal. Converting an analog signal to digital form introduces a low-level quantization noise into the signal due to finite resolution of digital systems. Once in digital form, the signal can be transmitted, stored, and processed without introducing additional noise or distortion using error detection and correction . Noise accumulation in analog systems can be minimized by electromagnetic shielding , balanced lines , low-noise amplifiers and high-quality electrical components. Nickel%E2%80%93metal hydride battery A nickel–metal hydride battery ( NiMH or Ni–MH )
1633-400: Is nickel hydroxide, and the negative electrode is hydrogen in the form of an interstitial metal hydride. Hydrophilic polyolefin nonwovens are used for separation. When fast-charging, it is advisable to charge the NiMH cells with a smart battery charger to avoid overcharging , which can damage cells. The simplest of the safe charging methods is with a fixed low current, with or without
1704-400: Is to monitor the change of voltage with time. When the battery is fully charged, the voltage across its terminals drops slightly. The charger can detect this and stop charging. This method is often used with nickel–cadmium cells, which display a large voltage drop at full charge. However, the voltage drop is much less pronounced for NiMH and can be non-existent at low charge rates, which can make
1775-533: The General Motors EV1 , first-generation Toyota RAV4 EV , Honda EV Plus , Ford Ranger EV and Vectrix scooter. Every first generation hybrid vehicle used NIMH batteries, most notably the Toyota Prius and Honda Insight , as well as later models including the Ford Escape Hybrid , Chevrolet Malibu Hybrid and Honda Civic Hybrid also use them. Stanford R. Ovshinsky invented and patented
1846-414: The memory effect ) from repeated partial discharge can occur, but is reversible with a few full discharge/charge cycles. A fully charged cell supplies an average 1.25 V/cell during discharge, declining to about 1.0–1.1 V/cell (further discharge may cause permanent damage in the case of multi-cell packs, due to polarity reversal of the weakest cell). Under a light load (0.5 amperes), the starting voltage of
1917-467: The nickel–hydrogen battery for satellite applications. Hydride technology promised an alternative, less bulky way to store the hydrogen. Research carried out by Philips Laboratories and France's CNRS developed new high-energy hybrid alloys incorporating rare-earth metals for the negative electrode. However, these suffered from alloy instability in alkaline electrolyte and consequently insufficient cycle life. In 1987, Willems and Buschow demonstrated
1988-457: The signal-to-noise ratio (SNR). As the signal is transmitted, copied, or processed, the unavoidable noise introduced in the signal path will accumulate as a generation loss , progressively and irreversibly degrading the SNR, until in extreme cases, the signal can be overwhelmed. Noise can show up as hiss and intermodulation distortion in audio signals, or snow in video signals . Generation loss
2059-566: The 9800X existed, most notably models that featured a 10-character alpha-numeric liquid crystal display (LCD), which had a green backlight. These uncommon variants were made for the Norwegian Storno and Italian SIP networks in the early 1990s. The Storno variants operated on NMT-450 and the SIP models were of the ETACS / RTMS-450 Dual Band. They kept the "MicroTAC" Blue logo on the screen,
2130-692: The 9800X-specific physical features, but kept the same basic form. Bone white models were also available as special editions to cellular providers in the US. An upscale version of the DPC, known as the MicroTAC 950 , or the MicroTAC Alpha in later years featured an 8-character green or orange dot-matrix LED display and the return of the alpha-numeric phonebook. The Alpha phones were "upscale" in that they had more user-programmable options. Also, Alpha phones featured
2201-535: The Digital Personal Communicator, or DPC, was introduced as a lower cost alternative to the 9800X. Light or dark gray in color, the phone featured a green or orange 7-character segment LED display. It closely resembled the 9800x in terms of the keypad design and background and the main body. Early DPCs of the 9800X-era featured the elongated antenna base, round-top side grips, and white-on-gray keypad. Later versions (most likely after 1991) lost
Motorola MicroTAC - Misplaced Pages Continue
2272-516: The International 5200, International 7500, and the International 8400, all running on the GSM 900 network. Many of these models are functionally identical but feature cosmetic differences or software upgrades. The International 8700, released in 1996, was fitted as a removable handset in the earliest Jaguar XK8 and Jaguar XKR luxury sports coupes and convertibles, and selected BMW models up to
2343-593: The Lite XL, was released around this time. It had a single-line green LED display and three Memory Location keys added. The Lite was quickly followed by the MicroTAC Ultra Lite. This phone was lighter and had longer battery life. In 1992, a new phone was released, the Ultra-Lite, which weighed 5.9 ounces (170 g), again holding the new record for the lightest phone available. This was due to it being
2414-534: The MicroTAC Lite was simultaneously released in some markets (including Asia) as the MicroTAC II . Several models were produced in different versions for different networks, including AMPS , ETACS, NMT , and JTACS. Some of these models (presumably the newer ones) share volume buttons and a rubber side grip with the later Ultra Lite model. The phones shipped with either a green backlit single-line LCD or
2485-575: The StarTAC, the MicroTAC 650E ("E" for Enhanced Features) received some feature upgrades, such as selectable ringer styles, but lost the alpha-numeric phonebook. The 650E was available in gray or black. The 650E was one of the better selling models in the US, along with the Elite and DPC 550. The MicroTAC was produced up until 1998, when sales declined with the increasing popularity of the StarTAC. The phone
2556-576: The Ti–Ni alloy structure and composition and patented its innovations. In 2008, more than two million hybrid cars worldwide were manufactured with NiMH batteries. In the European Union due to its Battery Directive , nickel–metal hydride batteries replaced Ni–Cd batteries for portable consumer use. About 22% of portable rechargeable batteries sold in Japan in 2010 were NiMH. In Switzerland in 2009,
2627-670: The US markets. One was the short-lived Micro DIGITAL model that operated on the AMPS and TDMA networks, and was similar in appearance to the Alpha model. The MicroTAC Lite was also available for the TDMA network. The other was the MicroTAC Select 6000e, with a design based on the International 8700. The Select models had large-format backlit LCDs, similar to those found on the MicroTAC 3000e and A725, which operated on CDMA networks. In 1996,
2698-431: The approach unreliable. Another option is to monitor the change of voltage with respect to time and stop when this becomes zero, but this risks premature cutoffs. With this method, a much higher charging rate can be used than with a trickle charge, up to 1 C . At this charge rate, Panasonic recommends to terminate charging when the voltage drops 5–10 mV per cell from the peak voltage. Since this method measures
2769-455: The battery market. NiMH batteries have replaced NiCd for many roles, notably small rechargeable batteries. NiMH batteries are commonly available in AA ( penlight -size) batteries. These have nominal charge capacities ( C ) of 1.1–2.8 Ah at 1.2 V, measured at the rate that discharges the cell in 5 hours. Useful discharge capacity is a decreasing function of the discharge rate, but up to
2840-640: The better), and on its physical size and charge capacity. Separators keep the two electrodes apart to slow electrical discharge while allowing the transport of ionic charge carriers that close the circuit during the passage of current . High-quality separators are critical for battery performance. The self-discharge rate depends upon separator thickness; thicker separators reduce self-discharge, but also reduce capacity as they leave less space for active components, and thin separators lead to higher self-discharge. Some batteries may have overcome this tradeoff by using more precisely manufactured thin separators, and
2911-411: The cell reaches full charge, most of the charging energy is converted to heat. This increases the rate of change of battery temperature, which can be detected by a sensor such as a thermistor . Both Panasonic and Duracell suggest a maximal rate of temperature increase of 1 °C per minute. Using a temperature sensor allows an absolute temperature cutoff, which Duracell suggests at 60 °C. With both
Motorola MicroTAC - Misplaced Pages Continue
2982-422: The cells retain 70–85% of their capacity when stored for one year at 20 °C (68 °F), compared to about half for normal NiMH batteries. They are otherwise similar to standard NiMH batteries, and can be charged in standard NiMH chargers. These cells are marketed as "hybrid", "ready-to-use" or "pre-charged" rechargeables. Retention of charge depends in large part on the battery's leakage resistance (the higher
3053-610: The charging process. A method for very rapid charging called in-cell charge control involves an internal pressure switch in the cell, which disconnects the charging current in the event of overpressure. One inherent risk with NiMH chemistry is that overcharging causes hydrogen gas to form, potentially rupturing the cell. Therefore, cells have a vent to release the gas in the event of serious overcharging. NiMH batteries are made of environmentally friendly materials. The batteries contain only mildly toxic substances and are recyclable. Voltage depression (often mistakenly attributed to
3124-499: The design remains essentially the same as in older NiCd units, except for an increase in the trickle-charging resistor value. Panasonic's handbook recommends that NiMH batteries on standby be charged by a lower duty cycle approach, where a pulse of a higher current is used whenever the battery's voltage drops below 1.3 V. This can extend battery life and use less energy. To prevent cell damage, fast chargers must terminate their charge cycle before overcharging occurs. One method
3195-542: The diminutive Motorola StarTAC was released, which provided fierce competition for MicroTAC. The phone received a redesign in 1996, with a more rounded case and thinner flip-lid. Two Memory Location keys were added to the phone. Base models were known as the DPC 650, which kept the 550's display. A more expensive model, the MicroTAC DPC 650E received the StarTAC 3000's 10-character LED display with separate battery and signal meters. It weighed 7.8 ounces (220 g). Like
3266-571: The display of its predecessor, the Motorola DynaTAC 8000X . However, dot-matrix displays of the time were still quite limited by today's standards. The inside of the flip piece had the "Motorola" logo on a diagonal, above thin blue diagonal lines. The badge on the front flip had a raised metallic Motorola logo, and "Micro T.A.C" in small blue letters above the display. The "micro" sized phone measured as long as over 9 inches (23 cm) long when open and weighed in 12.3 ounces (350 g) with
3337-757: The duration of single-charge use they outperform primary (such as alkaline) batteries. NiMH cells are advantageous for high-current-drain applications compared to alkaline batteries, largely due to their lower internal resistance. Typical alkaline AA-size batteries, which offer approximately 2.6 Ah capacity at low current demand (25 mA), provide only 1.3 Ah capacity with a 500 mA load. Digital cameras with LCDs and flashlights can draw over 1 A, quickly depleting them. NiMH cells can deliver these current levels without similar loss of capacity. Devices that were designed to operate using primary alkaline chemistry (or zinc-carbon/chloride) cells may not function with NiMH cells. However, most devices compensate for
3408-604: The end of 1998. With design underpinnings from the 8700, the dual-band International 8800 and 8900 (also known as the DB890) models were launched in 1997 and 1998 respectively. At the time of its launch, the International 8800 was the first mobile to work on both GSM 900 and 1800 bands. The International 8800 was rebadged for the Orange network as the Orange mr601 model. The success of their analogue microTAC handset blinded Motorola to
3479-417: The equivalent statistic was approximately 60%. This percentage has fallen over time due to the increase in manufacture of lithium-ion batteries: in 2000, almost half of all portable rechargeable batteries sold in Japan were NiMH. In 2015 BASF produced a modified microstructure that helped make NiMH batteries more durable, in turn allowing changes to the cell design that saved considerable weight, allowing
3550-537: The first phone that utilized NiMH batteries, although replacement batteries were often NiCDs because NiMHs were very expensive. The Ultra Lite was also the first phone with a vibrating ringer. In 1991, Motorola released the MicroTAC Classic which resembled the 1989 model, weighing in at 6.9 ounces (200 g). Several changes were carried over from the MicroTAC Lite: the antenna base was shortened,
3621-411: The good cells start to drive the discharged cell into reverse polarity (i.e. positive anode and negative cathode). Some cameras, GPS receivers and PDAs detect the safe end-of-discharge voltage of the series cells and perform an auto-shutdown, but devices such as flashlights and some toys do not. Irreversible damage from polarity reversal is a particular danger, even when a low voltage-threshold cutout
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#17327914840353692-597: The implications of the emerging GSM standard. This allowed Nokia to secure a competitive advantage with the Nokia 1011 that was released in 1992, a full two years ahead of the GSM version of the MicroTAC. This left only their Motorola International 3200 "brick" in the GSM market to compete with the Nokia 1011. Many in the industry regard this as the turning point in an industrial cellular landscape that Motorola had historically controlled. Several digital models were produced for
3763-574: The instantaneous signal voltage varies continuously with the pressure of the sound waves . In contrast, a digital signal represents the original time-varying quantity as a sampled sequence of quantized values. Digital sampling imposes some bandwidth and dynamic range constraints on the representation and adds quantization error . The term analog signal usually refers to electrical signals; however, mechanical , pneumatic , hydraulic , and other systems may also convey or be considered analog signals. An analog signal uses some property of
3834-492: The medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. In an electrical signal, the voltage , current , or frequency of the signal may be varied to represent the information. Any information may be conveyed by an analog signal; such a signal may be a measured response to changes in a physical variable, such as sound , light , temperature , position, or pressure . The physical variable
3905-473: The model for modern flip phones today. Its predecessor was the much larger and heavier Motorola DynaTAC "brick" phone, and it was succeeded by the Motorola StarTAC in 1996. "TAC" was an abbreviation of "Total Area Coverage" in all three models. The MicroTAC, released by Motorola on April 25, 1989, was the smallest and lightest phone available at the time. Upon its release, it made headlines across
3976-450: The ordinary Elite, which had a gray housing, a green LED display, and white lettering. The Elite series was a feature-packed phone and retailed for around $ 600. The phone included a first-ever two line display, for a total of 14 dot-matrix characters. There were also separate LED indicator meters for signal strength and battery, as well as a Menu Icon Display. The phone's software offered advanced menu features, and each category, when accessed,
4047-454: The red LED display was dropped for a 10-character LCD display, and the keys were changed from white to black. The phone was available on the ETACS network. There was a single-band GSM model available in the UK that took credit-card sized SIM cards . The Classic had the same "Motorola" over blue diagonal lines on the inside of the flip, but lost the metallic front badge and blue lettering. In 1991,
4118-448: The same black housing, but had different metallic badges in addition to the LCD. The original models can be distinguished by their elongated antenna base, white-translucent keys and gray keypad background. Accessories for the phone included car, desktop and overnight travel chargers, installed hands-free car kits, leather cases, and a selection of batteries. The slimmest battery then available
4189-492: The same core body, antenna, screen, keypad, and batteries, but lacked the flip-lid cover. The MicroTAC 650E lost the flip and Memory Location keys and gained arrow keys to become the Profile 300E . This Profile 300e phone was also called Metro1, the model on the sticker was S7956A and featured a 2.5 mm headset jack. Many MicroTAC models were available with the upscale VIP option. VIP phones were black with gold lettering, had
4260-470: The side grip arrow keys. Soon, an "affordable" DPC 550 came to the market. Almost identical to the Digital Personal Communicator, the DPC 550 featured little with the most basic of operations. On August 6, 1991, the MicroTAC Lite was introduced at 7.7 ounces (220 g). The Lite was the lightest phone available, continuing the record of the 9800X. It was essentially a slimmer version of the Alpha. Another model,
4331-499: The slim battery. The phone incorporated a built-in alpha-numeric phone book as one of the many standard features. A numerically organized menu allowed the user to select options for phone operations. Some of the many options included security codes, two phone number operations, a charge rate and currency calculator, secretarial memory scratchpads, hands-free operation, keypad tones, memory protection, phone number and name storage, as well as cellular system operation options. In addition to
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#17327914840354402-493: The specific energy to reach 140 watt-hours per kilogram. The negative electrode reaction occurring in a NiMH cell is On the positive electrode, nickel oxyhydroxide, NiO(OH), is formed: The reactions proceed left to right during charge and the opposite during discharge. The metal M in the negative electrode of a NiMH cell is an intermetallic compound. Many different compounds have been developed for this application, but those in current use fall into two classes. The most common
4473-465: The standard 12-button keypad, the MicroTAC had buttons for Power, Function, Name/Menu, End, Send, Clear, Store, and Recall. The left side of the phone featured two buttons for adjusting the volume up and down. While in alpha mode, the volume buttons toggled between upper-case and lower-case text. The model sold for between U.S. $ 2,495 and U.S. $ 3,495, and was produced into the early 1990s before being replaced by newer versions. Several variants of
4544-404: The voltage across the battery, a constant-current (rather than a constant-voltage) charging circuit is used. The temperature-change method is similar in principle to the Δ V method. Because the charging voltage is nearly constant, constant-current charging delivers energy at a near-constant rate. When the cell is not fully charged, most of this energy is converted to chemical energy. However, when
4615-483: The voltage drop of an alkaline battery as it discharges down to about 1 volt. Low internal resistance allows NiMH cells to deliver a nearly constant voltage until they are almost completely discharged. Thus battery-level indicators designed to read alkaline cells overstate the remaining charge when used with NiMH cells, as the voltage of alkaline cells decreases steadily during most of the discharge cycle. Lithium-ion batteries can deliver extremely high power and have
4686-469: The world. The phone was released as the "MicroTAC Pocket Cellular Telephone." The first MicroTACs were known as the Motorola 9800X, a continuation of the numerical name Motorola gave their phones in the 1980s. The MicroTAC was designed to fit into a shirt pocket. These very rare phones featured a black plastic housing and a red 8-character dot-matrix LED display, which was able to show more information than
4757-585: The Δ T and the Δ V charging methods, both manufacturers recommend a further period of trickle charging to follow the initial rapid charge. A resettable fuse in series with the cell, particularly of the bimetallic strip type, increases safety. This fuse opens if either the current or the temperature gets too high. Modern NiMH cells contain catalysts to handle gases produced by over-charging: However, this only works with overcharging currents of up to 0.1 C (that is, nominal capacity divided by ten hours). This reaction causes batteries to heat, ending
4828-406: Was indicated with green icons at the bottom of the display. Categories included Phone Book, Timers, Security, Tone Control, Phone Options, and Answering Machine / Messaging. This was the first mobile phone to have a built-in, recordable answering machine. It was also the first mobile phone to use a lithium-ion battery. A series of GSM models was produced beginning in 1994, mostly in the UK, such as
4899-637: Was not made available for mainstream use. The fate of these units is currently unknown; presumably most of them would have been destroyed for security reasons but at least one example survives as a museum exhibit. Design-wise, the CipherTAC took after the Elite VIP. The MicroTAC body was also used as the base model for the Motorola TeleTAC and the Flare series . The TeleTAC and Flare phones used
4970-521: Was still relatively commonplace into the early 2000s. However, due to its large size and weight, many owners of the phone upgraded to smaller models like the StarTAC. The CipherTAC was a spin-off of the MicroTAC series, running on the CDMA network. It offered unrecoverable, encrypted communication and was purpose-built in 1998 for the Secretary of State (then Madeleine Albright ) and other officials. It
5041-530: Was the Slim and Slim Extended (Life), followed by the Standard, XT, and Talk-Pak XT batteries. The Talk-Pak XT and XT used Nickel Metal-Hydride while the others used Nickel Cadmium . A Lithium Ion battery was introduced in 1994. The early 9800X-era MicroTACs were the only phones to have the microphone and ringer in the mouthpiece. These components were moved to the main phone body in all other models. In 1989,
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