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一、电子秤 例题1:图1-1是某同学在科技活动中自制的 电子秤原理图,该电 子秤利用电压表的 示数来指示物体的 质量,托盘与电阻可 忽略的弹簧相连,托 盘与弹簧的质量均 不计.滑动变阻器的 滑动端与弹簧相连,托盘没有放重物时,电压表示 数为零,设变阻器总电阻为R,总长度为L.电源的 电动势为ε,内阻为r,限流R0,弹簧劲度系数为k, 若不计一切摩擦和其他阻力.
First, the electronic scale example 1: Figure 1-1 is a classmate’s self-made electronic scales in the scientific and technological activities of the schematic diagram, the electronic scales use the voltage meter to indicate the quality of the object, the tray and the resistor can be ignored spring connected to the tray The mass of the spring is not counted. The sliding end of the sliding rheostat is connected with the spring. When the weight of the tray is not released, the voltage is expressed as zero. The total resistance of the varistor is R and the total length is L. The electromotive force of the power supply is ε, the internal resistance is r, current limit R0, spring stiffness is k, if all friction and other resistance are ignored.