The

Sharp Sharp or SHARP may refer to: Acronyms * SHARP (helmet ratings) (Safety Helmet Assessment and Rating Programme), a British motorcycle helmet safety rating scheme * Self Help Addiction Recovery Program, a charitable organisation founded in 199 ...

QT-8B Micro Compet, a portable electronic desktop

calculator An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics. The first solid-state electronic calculator was created in the early 1960s. Pocket-si ...

, was the first mass-produced calculator to be battery-powered. Introduced in mid-1970, it was based on its immediate predecessor, the QT-8D introduced in late 1969, but it replaced the QT-8D's integrated

power supply A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, electric current, current, and frequency to power ...

with a

rechargeable A rechargeable battery, storage battery, or secondary cell (formally a type of energy accumulator), is a type of electrical battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or primar ...

battery pack A battery pack is a set of any number of (preferably) identical Battery (electricity), batteries or individual battery cells. They may be configured in a series, parallel or a mixture of both to deliver the desired voltage and current. The term ' ...

. It has the same calculating

integrated circuits An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

as the QT-8D and is of similar appearance and dimensions; the power supply is the only major difference. The QT-8B's release price in Japan was 117,000

yen The is the official currency of Japan. It is the third-most traded currency in the foreign exchange market, after the United States dollar and the euro. It is also widely used as a third reserve currency after the US dollar and the euro. T ...

. The U.S. price in mid-1971 was $495, equivalent to about $2,700 in 2010. These prices were somewhat higher than those for the preceding QT-8D. The QT-8B's battery pack contains six nickel-cadmium C batteries connected in

series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used i ...

, giving a total

voltage Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...

of 7.5

volt The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ...

s and, with the original batteries, a total capacity of 1200

milliampere-hour An ampere-hour or amp-hour (symbol: A⋅h or A h; often simplified as Ah) is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for o ...

s. (Modern nickel-cadmium C batteries have much greater capacity.) For recharging, the calculator accepts 12-volt DC external power, with an input power rating of 6.5

watt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

s. Normally the calculator is recharged from

AC power In an electric circuit, instantaneous power is the time rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the d ...

by plugging it into an external charging station (model QTA-2) which is a little longer than the calculator and has a plug that fits into the calculator's charging socket. The calculator sits on top of the base of this charging station and can be used while charging; it can also be locked into the station for extra stability. An adapter for using 12-volt DC automobile power was also available. The display used is

vacuum fluorescent display A vacuum fluorescent display (VFD) is a display device once commonly used on consumer electronics equipment such as video cassette recorders, car audio, car radios, and microwave ovens. A VFD operates on the principle of cathodoluminescence, ...

.There is a slight difference between the QT-8D and the QT-8B in the operation of the right-hand display tube, which contains both a minus-sign indicator and a large dot. On the QT-8D, this dot is used as an overflow error indicator. But on the QT-8B, it acts as a low-battery indicator; overflow errors are signalled by displaying all zeroes with all the decimal point indicators lit. Sharp made an OEM version of the QT-8B for Burroughs, the Burroughs C3146, which has some significant differences from Sharp's own version. The QT-8B needs an external station for recharging its batteries and for AC operation, but the C3146 has its AC power supply built in, along with the batteries and charging electronics, and can thus be plugged directly into AC power. Since the C3146 has both a battery pack and an AC power supply, it also has a larger case to accommodate them. Like the Sharp, the Burroughs machine can also use 12-volt DC automobile power via an adapter. Otherwise, the C3146's electronics are identical to those of the QT-8B.

References

External links

Sharp QT-8B in Curtamania
(In English) {{Sharp Corporation QT-8B