简述有源应答器和无源应答器的用途和区别。
["\u7b54\uff1a\u65e0\u6e90\u5e94\u7b54\u5668\u2014\u2014\u4e0e\u5916\u754c\u65e0\u7269\u7406\u8fde\u63a5\uff0c\u5411\u5217\u8f66\u4f20\u9001\u56fa\u5b9a\u4fe1\u606f,\u6709\u6e90\u5e94\u7b54\u5668\u2014\u2014\u901a\u8fc7\u7535\u7f06\u4e0eLEU\u8fde\u63a5\uff0c\u5411\u5217\u8f66\u4f20\u9001\u5b9e\u65f6\u53ef\u53d8\u4fe1\u606f\u5916\u89c2\u76f8\u540c\uff1a\u6709\u6e90\u5e94\u7b54\u5668\u8fde\u63a5\u7535\u7f06;\u53d1\u9001\u4fe1\u606f: \u65e0\u6e90\u5e94\u7b54\u5668\u53d1\u9001\u81ea\u8eab\u9884\u5b58\u4fe1\u606f;\u6709\u6e90\u5e94\u7b54\u5668\u53d1\u9001\u81eaLEU\u6765\u7684\u4fe1\u606f\uff0c\u5f53\u7535\u7f06\u65ad\u7ebf\u65f6\u53d1\u9001\u81ea\u8eab\u9884\u5b58\u4fe1\u606f\uff08\u9ed8\u8ba4\/\u7f3a\u7701\u62a5\u6587\uff09\""]