{"id":1390,"date":"2024-11-12T10:36:37","date_gmt":"2024-11-12T10:36:37","guid":{"rendered":"https:\/\/nbaem.com\/?p=1390"},"modified":"2024-11-12T10:37:58","modified_gmt":"2024-11-12T10:37:58","slug":"how-to-measure-magnet-strength","status":"publish","type":"post","link":"https:\/\/nbaem.com\/vi\/how-to-measure-magnet-strength\/","title":{"rendered":"L\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m?"},"content":{"rendered":"

Nam ch\u00e2m, d\u00f9 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c \u1ee9ng d\u1ee5ng c\u00f4ng nghi\u1ec7p hay trong c\u00e1c s\u1ea3n ph\u1ea9m b\u1ea1n c\u00f3 quanh nh\u00e0, t\u1ea1o ra m\u1ed9t tr\u01b0\u1eddng t\u1eeb c\u00f3 th\u1ec3 m\u1ea1nh h\u01a1n ho\u1eb7c y\u1ebfu h\u01a1n. Vi\u1ec7c bi\u1ebft c\u00e1ch \u0111o \u0111\u1ed9 m\u1ea1nh n\u00e0y r\u1ea5t quan tr\u1ecdng, \u0111\u1eb7c bi\u1ec7t khi b\u1ea1n s\u1eed d\u1ee5ng nam ch\u00e2m trong c\u00e1c \u1ee9ng d\u1ee5ng m\u00e0 \u0111\u1ed9 tin c\u1eady v\u00e0 hi\u1ec7u su\u1ea5t l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t. Trong h\u01b0\u1edbng d\u1eabn n\u00e0y, ch\u00fang t\u00f4i s\u1ebd n\u00f3i v\u1ec1 c\u00e1ch \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m, c\u00e1c \u0111\u01a1n v\u1ecb kh\u00e1c nhau b\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng, v\u00e0 c\u00e1c ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ec3 th\u1ef1c hi\u1ec7n \u0111i\u1ec1u \u0111\u00f3 m\u1ed9t c\u00e1ch ch\u00ednh x\u00e1c.<\/p>\n

C\u00e1c lo\u1ea1i nam ch\u00e2m: Nam ch\u00e2m v\u0129nh c\u1eedu v\u00e0 Nam ch\u00e2m \u0111i\u1ec7n<\/strong><\/h2>\n

Tr\u01b0\u1edbc khi \u0111i v\u00e0o c\u00e1ch \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m, ch\u00fang ta c\u1ea7n n\u00f3i v\u1ec1 hai lo\u1ea1i nam ch\u00e2m: nam ch\u00e2m v\u0129nh c\u1eedu v\u00e0 nam ch\u00e2m \u0111i\u1ec7n.<\/p>\n

Nam ch\u00e2m v\u0129nh c\u1eedu gi\u1eef t\u1eeb t\u00ednh m\u00e3i m\u00e3i sau khi \u0111\u00e3 \u0111\u01b0\u1ee3c magnetize.<\/p>\n

Nam ch\u00e2m \u0111i\u1ec7n ch\u1ec9 t\u1ea1o ra tr\u01b0\u1eddng t\u1eeb khi b\u1ea1n c\u1ea5p \u0111i\u1ec7n cho ch\u00fang. Khi ng\u1eebng c\u1ea5p \u0111i\u1ec7n, ch\u00fang s\u1ebd d\u1eebng l\u1ea1i.<\/p>\n

C\u00e1c \u0111\u01a1n v\u1ecb \u0111o \u0111\u1ed9 m\u1ea1nh t\u1eeb tr\u01b0\u1eddng<\/strong><\/h2>\n

B\u1ea1n c\u00f3 th\u1ec3 \u0111o \u0111\u1ed9 m\u1ea1nh t\u1eeb tr\u01b0\u1eddng b\u1eb1ng c\u00e1c \u0111\u01a1n v\u1ecb kh\u00e1c nhau. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 c\u00e1c \u0111\u01a1n v\u1ecb ph\u1ed5 bi\u1ebfn nh\u1ea5t b\u1ea1n s\u1ebd th\u1ea5y:<\/p>\n

    \n
  1. Tesla (T)<\/strong>: Tesla l\u00e0 \u0111\u01a1n v\u1ecb ti\u00eau chu\u1ea9n \u0111\u1ec3 \u0111o m\u1eadt \u0111\u1ed9 c\u1ee7a tr\u01b0\u1eddng t\u1eeb, ho\u1eb7c \u0111\u1ed9 d\u01b0 t\u1eeb c\u1ee7a n\u00f3. N\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c bi\u1ec3u di\u1ec5n theo nhi\u1ec1u c\u00e1ch kh\u00e1c nhau b\u1eb1ng c\u00e1c \u0111\u01a1n v\u1ecb khoa h\u1ecdc kh\u00e1c, ch\u1eb3ng h\u1ea1n nh\u01b0<\/li>\n
  2. Gauss (G)<\/strong>: Gauss \u0111o \u0111\u1ed9 l\u01b0u gi\u1eef t\u1eeb, t\u1ee9c l\u00e0 \u0111\u1ed9 t\u1eeb c\u00f2n l\u1ea1i trong v\u1eadt li\u1ec7u sau khi lo\u1ea1i b\u1ecf tr\u01b0\u1eddng t\u1eeb b\u00ean ngo\u00e0i. M\u1ed9t gauss b\u1eb1ng 10^-4 tesla v\u00e0 th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c \u1ee9ng d\u1ee5ng th\u01b0\u01a1ng m\u1ea1i \u0111\u1ec3 bi\u1ec3u th\u1ecb \u0111\u1ed9 m\u1ea1nh c\u1ee7a tr\u01b0\u1eddng t\u1eeb.<\/li>\n
  3. Oersted (Oe)<\/strong>: \u0110\u01a1n v\u1ecb n\u00e0y \u0111o \u0111\u1ed9 c\u1ee9ng t\u1eeb c\u1ee7a nam ch\u00e2m, ho\u1eb7c kh\u1ea3 n\u0103ng ch\u1ed1ng m\u1ea5t t\u1eeb c\u1ee7a n\u00f3. \u0110\u1ed9 c\u1ee9ng t\u1eeb l\u00e0 l\u1ef1c c\u1ea7n thi\u1ebft \u0111\u1ec3 gi\u1ea3m t\u1eeb t\u00ednh c\u1ee7a nam ch\u00e2m xu\u1ed1ng b\u1eb1ng kh\u00f4ng. M\u1ed9t oersted \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 1 dyne tr\u00ean m\u1ed9t maxwell ho\u1eb7c kho\u1ea3ng 79.577 ampe tr\u00ean m\u00e9t.<\/li>\n
  4. Kilogram (kg)<\/strong>: Trong l\u0129nh v\u1ef1c t\u1eeb tr\u01b0\u1eddng, kilogram \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111o l\u1ef1c h\u00fat c\u1ee7a nam ch\u00e2m, ho\u1eb7c l\u01b0\u1ee3ng tr\u1ecdng l\u01b0\u1ee3ng m\u00e0 nam ch\u00e2m c\u00f3 th\u1ec3 gi\u1eef tr\u01b0\u1edbc khi t\u00e1ch kh\u1ecfi b\u1ec1 m\u1eb7t. L\u1ef1c h\u00fat th\u01b0\u1eddng \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ecb b\u1eb1ng kilogram ho\u1eb7c pound.<\/li>\n<\/ol>\n

    Ph\u01b0\u01a1ng ph\u00e1p \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m<\/strong><\/h2>\n
      \n
    1. M\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng\/Gaussmeter
      \n<\/strong>M\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng l\u00e0 m\u1ed9t thi\u1ebft b\u1ecb \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a tr\u01b0\u1eddng t\u1eeb t\u1ea1i m\u1ed9t \u0111i\u1ec3m c\u1ee5 th\u1ec3 trong kh\u00f4ng gian. B\u1ea1n s\u1ebd th\u1ea5y hai lo\u1ea1i ch\u00ednh c\u1ee7a m\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng:
      \nM\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng d\u1ea1ng scalar: C\u00e1c thi\u1ebft b\u1ecb n\u00e0y \u0111o gi\u00e1 tr\u1ecb v\u00f4 h\u01b0\u1edbng c\u1ee7a c\u01b0\u1eddng \u0111\u1ed9 tr\u01b0\u1eddng t\u1eeb. V\u00ed d\u1ee5 bao g\u1ed3m m\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng proton precession v\u00e0 m\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng Overhauser.
      \nM\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng d\u1ea1ng vector: C\u00e1c thi\u1ebft b\u1ecb n\u00e0y \u0111o c\u1ea3 c\u01b0\u1eddng \u0111\u1ed9 v\u00e0 h\u01b0\u1edbng c\u1ee7a tr\u01b0\u1eddng t\u1eeb. V\u00ed d\u1ee5 bao g\u1ed3m c\u00e1c thi\u1ebft b\u1ecb can thi\u1ec7p l\u01b0\u1ee3ng t\u1eed si\u00eau d\u1eabn (SQUID), m\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng cu\u1ed9n t\u00ecm ki\u1ebfm, v\u00e0 m\u00e1y \u0111o t\u1eeb tr\u01b0\u1eddng hi\u1ec7u \u1ee9ng Hall.
      \nC\u1ea3m bi\u1ebfn t\u1eeb tr\u01b0\u1eddng ho\u1ea1t \u0111\u1ed9ng theo nhi\u1ec1u c\u00e1ch kh\u00e1c nhau. V\u00ed d\u1ee5, c\u1ea3m bi\u1ebfn t\u1eeb tr\u01b0\u1eddng hi\u1ec7u \u1ee9ng Hall ph\u00e1t hi\u1ec7n tr\u01b0\u1eddng t\u1eeb b\u1eb1ng c\u00e1ch quan s\u00e1t c\u00e1ch tr\u01b0\u1eddng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn d\u00f2ng \u0111i\u1ec7n. C\u1ea3m bi\u1ebfn t\u1eeb c\u1ea3m \u1ee9ng \u0111o m\u1ee9c \u0111\u1ed9 t\u1eeb h\u00f3a c\u1ee7a m\u1ed9t v\u1eadt li\u1ec7u khi \u0111\u1eb7t n\u00f3 trong m\u1ed9t tr\u01b0\u1eddng t\u1eeb.<\/li>\n<\/ol>\n
        \n
      1. Thi\u1ebft b\u1ecb \u0111o flux<\/strong>
        \nThi\u1ebft b\u1ecb \u0111o flux \u0111o l\u01b0\u1ee3ng t\u1eeb th\u00f4ng, t\u1ee9c l\u00e0 t\u1ed5ng l\u01b0\u1ee3ng tr\u01b0\u1eddng t\u1eeb \u0111i qua m\u1ed9t di\u1ec7n t\u00edch nh\u1ea5t \u0111\u1ecbnh. N\u00f3 \u0111\u1eb7c bi\u1ec7t h\u1eefu \u00edch trong c\u00e1c \u1ee9ng d\u1ee5ng c\u1ea7n hi\u1ec3u r\u00f5 l\u01b0\u1ee3ng n\u0103ng l\u01b0\u1ee3ng t\u1eeb tr\u01b0\u1eddng \u0111ang ch\u1ea3y qua m\u1ed9t kh\u00f4ng gian c\u1ee5 th\u1ec3. Thi\u1ebft b\u1ecb \u0111o flux d\u1ef1a tr\u00ean \u0111\u1ecbnh lu\u1eadt c\u1ea3m \u1ee9ng \u0111i\u1ec7n t\u1eeb c\u1ee7a Faraday, n\u00f3i r\u1eb1ng m\u1ed9t tr\u01b0\u1eddng t\u1eeb bi\u1ebfn \u0111\u1ed5i s\u1ebd g\u00e2y ra m\u1ed9t \u0111i\u1ec7n \u00e1p trong m\u1ed9t d\u00e2y d\u1eabn. Thi\u1ebft b\u1ecb \u0111o flux \u0111o c\u00e1c thay \u0111\u1ed5i \u0111i\u1ec7n \u00e1p \u0111\u00f3 v\u00e0 t\u00ednh to\u00e1n l\u01b0\u1ee3ng t\u1eeb th\u00f4ng.<\/li>\n<\/ol>\n
          \n
        1. Ki\u1ec3m tra l\u1ef1c h\u00fat t\u1eeb
          \n<\/strong>Ki\u1ec3m tra l\u1ef1c h\u00fat t\u1eeb \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m b\u1eb1ng c\u00e1ch x\u00e1c \u0111\u1ecbnh l\u1ef1c c\u1ea7n thi\u1ebft \u0111\u1ec3 k\u00e9o n\u00f3 ra kh\u1ecfi m\u1ed9t m\u1ea3nh kim lo\u1ea1i. B\u1ea1n s\u1eed d\u1ee5ng c\u00e1c b\u00e0i ki\u1ec3m tra n\u00e0y \u0111\u1ec3 ki\u1ec3m tra ch\u1ea5t l\u01b0\u1ee3ng c\u1ee7a nam ch\u00e2m v\u00e0 \u0111\u1ea3m b\u1ea3o n\u00f3 c\u00f3 \u0111\u1ed9 m\u1ea1nh ph\u00f9 h\u1ee3p v\u1edbi y\u00eau c\u1ea7u c\u1ee7a b\u1ea1n. \u0110\u1ec3 th\u1ef1c hi\u1ec7n ki\u1ec3m tra l\u1ef1c h\u00fat t\u1eeb, b\u1ea1n g\u1eafn m\u1ed9t m\u1ea3nh kim lo\u1ea1i v\u00e0o m\u00f3c r\u1ed3i k\u00e9o n\u00f3 ra kh\u1ecfi nam ch\u00e2m theo g\u00f3c 90 \u0111\u1ed9 cho \u0111\u1ebfn khi nam ch\u00e2m nh\u1ea3 ra. L\u1ef1c c\u1ea7n thi\u1ebft \u0111\u1ec3 nam ch\u00e2m nh\u1ea3 ra ch\u00ednh l\u00e0 l\u1ef1c k\u00e9o c\u1ee7a b\u1ea1n t\u00ednh b\u1eb1ng kilogram ho\u1eb7c pound.<\/li>\n<\/ol>\n

           <\/p>\n

          C\u00e1c y\u1ebfu t\u1ed1 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn \u0111o l\u01b0\u1eddng \u0111\u1ed9 m\u1ea1nh t\u1eeb tr\u01b0\u1eddng<\/strong><\/h2>\n

          \u0110\u1ed9 ch\u00ednh x\u00e1c c\u1ee7a c\u00e1c ph\u00e9p \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m c\u00f3 th\u1ec3 b\u1ecb \u1ea3nh h\u01b0\u1edfng b\u1edfi m\u1ed9t s\u1ed1 y\u1ebfu t\u1ed1 m\u00f4i tr\u01b0\u1eddng. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t v\u00e0i v\u00ed d\u1ee5:<\/p>\n

            \n
          1. Nhi\u1ec7t \u0111\u1ed9:<\/strong> Nhi\u1ec7t \u0111\u1ed9 cao c\u00f3 th\u1ec3 l\u00e0m gi\u1ea3m \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m, \u0111\u1eb7c bi\u1ec7t khi nhi\u1ec7t \u0111\u1ed9 v\u01b0\u1ee3t qu\u00e1 nhi\u1ec7t \u0111\u1ed9 ho\u1ea1t \u0111\u1ed9ng t\u1ed1i \u0111a c\u1ee7a nam ch\u00e2m. Nhi\u1ec7t \u0111\u1ed9 th\u1ea5p c\u00f3 th\u1ec3 l\u00e0m nam ch\u00e2m m\u1ea1nh h\u01a1n v\u00ec l\u1ea1nh l\u00e0m ch\u1eadm l\u1ea1i chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a c\u00e1c h\u1ea1t t\u1eeb.<\/li>\n
          2. \u0110\u1ed9 \u1ea9m v\u00e0 \u0110i\u1ec7n n\u0103ng: <\/strong>\u0110\u1ed9 \u1ea9m v\u00e0 \u0111i\u1ec7n n\u0103ng c\u0169ng c\u00f3 th\u1ec3 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m. V\u00ed d\u1ee5, m\u1ed9t s\u1ed1 nam ch\u00e2m \u0111\u1ea5t hi\u1ebfm, nh\u01b0 nam ch\u00e2m neodymium, c\u00f3 th\u1ec3 b\u1ecb \u0103n m\u00f2n, l\u00e0m gi\u1ea3m \u0111\u1ed9 m\u1ea1nh c\u1ee7a ch\u00fang.<\/span><\/li>\n<\/ol>\n

             <\/p>\n

            L\u1ef1a ch\u1ecdn nam ch\u00e2m ph\u00f9 h\u1ee3p cho \u1ee9ng d\u1ee5ng c\u1ee7a b\u1ea1n<\/h2>\n

            Khi b\u1ea1n t\u00ecm ki\u1ebfm m\u1ed9t nam ch\u00e2m cho \u1ee9ng d\u1ee5ng c\u1ee7a m\u00ecnh, b\u1ea1n c\u1ea7n xem x\u00e9t c\u1ea3 \u0111\u1ed9 m\u1ea1nh v\u00e0 \u0111\u1eb7c t\u00ednh v\u1eadt li\u1ec7u. C\u00e1c lo\u1ea1i nam ch\u00e2m kh\u00e1c nhau c\u00f3 m\u1ee9c \u0111\u1ed9 m\u1ea1nh v\u00e0 \u0111\u1ed9 \u1ed5n \u0111\u1ecbnh nhi\u1ec7t kh\u00e1c nhau.<\/p>\n