Search results
Results from the WOW.Com Content Network
HP-19C calculator HP-29C with AC-powered battery charger. The HP-19C and HP-29C were scientific/engineering pocket calculators made by Hewlett-Packard between 1977 and 1979. They were the most advanced and last models of the "20" family (compare HP-25) and included Continuous Memory (battery-backed CMOS memory) as a standard feature.
HP-19B, introduced on 4 January 1988, along with the HP-17B, HP-27S and the HP-28S, and replaced by the HP-19BII (F1639A) in January 1990, [2] was a simplified Hewlett Packard business model calculator, like the 17B.
A battery charger, recharger, or simply charger, [1] [2] is a device that stores energy in an electric battery by running current through it. The charging protocol—how much voltage , amperes, current, for how long and what to do when charging is complete—depends on the size and type of the battery being charged.
Button, coin, or watch cells. A button cell, watch battery, or coin battery is a small battery made of a single electrochemical cell and shaped as a squat cylinder typically 5 to 25 mm (0.197 to 0.984 in) in diameter and 1 to 6 mm (0.039 to 0.236 in) high – resembling a button.
In practice, it depends on the capability of the charger. The battery capacity C is expressed in Ah units, typically the C 20 value based on a 20-hour discharge time. [3] The charging current (in A units) can be written as C/t where t is a time. For example, for a battery with C = 40 Ah, a current C/10 is equal to 4 A. The charging current is a ...
If a battery has been completely discharged (e.g. the car lights were left on overnight) and next is given a fast charge for only a few minutes, then during the short charging time it develops only a charge near the interface. The battery voltage may rise to be close to the charger voltage so that the charging current decreases significantly.
−1: If the subtraction button − is pressed after the multiplication ×, it is interpreted as a correction of the × rather than a minus sign, so that 4 − 5 is calculated. 20: If the change-sign button ± is pressed before the 5, it isn't interpreted as −5, and 4 × 5 is calculated.
Quick Charge is a proprietary technology that can charge battery-powered devices, primarily mobile phones, at power levels exceeding the 7.5 watts (5 volts at 1.5 amps) supported by the USB BC 1.2 standard, using existing USB cables. The higher voltage available allows more power (watts) to be supplied through wires without excessive heating.