电压过大和电流过大分别会怎样? 电器被烧坏是电压过大还是电阻过大？
推荐回答（2个）
在日常家用（非工程非工业）范围内，大电流意味着发热量大，大电压意味着被击穿的可能性大。所以如果一个用电器被烧坏了，一定是电流大的原因，如果是被击穿短路了，一定是电压高的原因。
大电流意味着有强大的输出能力，电源内阻很小，如果在保持大电流输出的同时，电压保持恒定且有较高的数值，则其电源输出功率高，如果电压随之下降较大，则总体输出功率有限。大电压也要考虑到输出电流的情况，例如我们常见的蚊拍，电压达到两千伏特以上，可以瞬间把蚊子击的支离破碎，也有可能对人体造成一定的伤害，警用电棍倘若使用不当，电流通过心脏可能使犯人致死。但是绝对不能推动高压电动机，究其原因，区区两节电池能有多大的功率？电流太小了。我们脱毛衣时会有闪光，电压可以击穿空气，但是人体仅有轻微触电感觉，并无危险就是一个例子。高电压加上强电流，就是很牛的功率源，好像闪电⚡️高达上亿伏特，同时很大的电流使空气瞬间电离，空气急剧膨胀发出爆裂轰鸣声，她瞬间释放的能量极大，但是不能持久，也难以存储利用，作用时间极短，于是才有振聋发聩之效果，三国演义中曹操刘备煮酒论英雄，“一震之威，乃至于此！”可见雷电威力之大。有的电源，例如电焊机，考虑到实际用途和安全操作，并不需要高的电压，却需要极其强大的电流，才能利用电流热效应快速融化电焊条。我们看到电弧强光，非常骇人，可是人体接触这样低的电压却能安然无恙。可知电流和电压根本是两回事。见过一个视频，几千伏安容量的变压器，副线圈只有区区几圈，当然线径很粗，用一把大扳手做负载，一会儿就发红，从开始融化直至面目全非，不到半分钟时间！显见电流极大(估计可达几百至上千安培)，而电压不过区区1.7伏！
220V的入户市电，我们串接上一个两微法的无极性电容器，再串接上一个12伏特小灯泡💡，可能会微亮，电流是不大的，切断后串入万用表电压档，可以发现仍然有220伏特！但是此时灯泡不亮了，因为理想的电压表电阻趋于无穷大，导致电流极小。因此如果我们把灯泡撤去，用手去摸会很危险可能被电死的，因为根据串联分压原理，人体电阻比较大，大部分电压分配到人体上，远远超过了安全电压了。电压和电流，既紧密联系又有区别，其关系正如水压与水流，水对管壁的压力是水流的动因，电压是闭合回路前提下电流得以形成的根本原因。
电压过大会：1）就会使用电器的电流增加，在用电器内产生的热量增加，导致用电器被烧坏。
2）超过用电器的耐压时，用电器会被击穿短路，电流急剧增大导致烧坏。
电流过大会：结果同上。电流大的原因1）由电压过大引起。2）因用电器本身质量差或人为造成的。
用电器被烧坏的原因：电压过高、本身质量低劣、人为失误。不是电阻大。
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