{"id":18517,"date":"2020-11-06T03:56:51","date_gmt":"2020-11-06T03:56:51","guid":{"rendered":"https:\/\/hocvienit.vn\/?p=18517"},"modified":"2024-07-03T12:42:23","modified_gmt":"2024-07-03T05:42:23","slug":"jfet-la-gi-tim-hieu-ve-jfet","status":"publish","type":"post","link":"https:\/\/hocvienit.vn\/?p=18517","title":{"rendered":"JFET l\u00e0 g\u00ec? T\u00ecm hi\u1ec3u v\u1ec1 JFET"},"content":{"rendered":"

FET \u0111\u01b0\u1ee3c chia ra th\u00e0nh JFET v\u00e0 MOSFET<\/strong><\/a>. Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang ta s\u1ebd c\u00f9ng t\u00ecm hi\u1ec3u v\u1ec1 JFET l\u00e0 g\u00ec?<\/strong> C\u1ea5u t\u1ea1o v\u00e0 k\u00fd hi\u1ec7u c\u1ee7a JFET c\u0169ng nh\u01b0 nguy\u00ean l\u00fd ho\u1ea1t \u0111\u1ed9ng c\u1ee7a n\u00f3 nh\u00e9.<\/span><\/p>\n

\"JFET
JFET l\u00e0 g\u00ec? T\u00ecm hi\u1ec3u v\u1ec1 JFET<\/span><\/figcaption><\/figure>\n

JFET l\u00e0 g\u00ec?<\/strong><\/span><\/h2>\n

JFET (Junction Field Effect Transistor) hay c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 Transistor hi\u1ec7u \u1ee9ng tr\u01b0\u1eddng c\u1ed5ng n\u1ed1i ho\u1eb7c FET n\u1ed1i. \u0110\u00e2y l\u00e0 m\u1ed9t lo\u1ea1i \u0111\u01a1n gi\u1ea3n c\u1ee7a <\/span>FET<\/a><\/strong> (Transistor hi\u1ec7u \u1ee9ng tr\u01b0\u1eddng). N\u00f3 th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng l\u00e0m ph\u1ea7n t\u1eed chuy\u1ec3n m\u1ea1ch \u0111i\u1ec1u khi\u1ec3n \u0111i\u1ec7n t\u1eed ho\u1eb7c s\u1eed d\u1ee5ng l\u00e0m ph\u1ea7n t\u1eed khu\u1ebfch \u0111\u1ea1i hay l\u00e0m \u0111i\u1ec7n tr\u1edf \u0111i\u1ec1u khi\u1ec3n b\u1edfi \u0111i\u1ec7n \u00e1p trong c\u00e1c m\u1ea1ch \u0111i\u1ec7n t\u1eed\u2026<\/span><\/span><\/p>\n

C\u1ea5u t\u1ea1o c\u1ee7a JFET<\/strong><\/span><\/h2>\n

Tr\u00ean m\u1ed9t thanh b\u00e1n d\u1eabn h\u00ecnh tr\u1ee5 c\u00f3 n\u1ed3ng \u0111\u1ed9 t\u1ea1p ch\u1ea5t t\u01b0\u01a1ng \u0111\u1ed1i l\u1edbn (\u0110i\u1ec7n tr\u1edf su\u1ea5t kh\u00e1 l\u1edbn), ng\u01b0\u1eddi ta thi\u1ebft k\u1ebf \u0111\u00e1y tr\u00ean v\u00e0 \u0111\u00e1y d\u01b0\u1edbi l\u1ea7n l\u01b0\u1ee3t \u0111\u01b0\u1ee3c ti\u1ebfp x\u00fac kim lo\u1ea1i \u0111\u1ec3 cho ra hai c\u1ef1c t\u01b0\u01a1ng \u1ee9ng l\u00e0 c\u1ef1c m\u00e1ng (C\u1ef1c tho\u00e1t) v\u00e0 c\u1ef1c ngu\u1ed3n.\u00a0<\/span>Ti\u1ebfp \u0111\u1ebfn, ng\u01b0\u1eddi ta t\u1ea1o m\u1ed9t m\u1ed1i P – N v\u00f2ng theo chu vi c\u1ee7a thanh b\u00e1n d\u1eabn. Kim lo\u1ea1i ti\u1ebfp x\u00fac\u00a0<\/span>v\u1edbi m\u1eabu b\u00e1n d\u1eabn m\u1edbi, \u0111\u01b0a ra ngo\u00e0i c\u1ef1c c\u1ed5ng (c\u1eeda).<\/span><\/span><\/p>\n

Trong \u0111\u00f3:<\/span><\/p>\n

D<\/strong> (Drain): C\u1ef1c m\u00e1ng (C\u1ef1c tho\u00e1t).<\/span><\/p>\n

G<\/strong> (Gate): C\u1ef1c c\u1ed5ng (C\u1ef1c c\u1eeda).<\/span><\/p>\n

S<\/strong> (Source): C\u1ef1c ngu\u1ed3n.<\/span><\/p>\n

– C\u1ef1c D v\u00e0 c\u1ef1c S \u0111\u01b0\u1ee3c k\u1ebft n\u1ed1i v\u00e0o k\u00eanh N.<\/span><\/p>\n

– C\u1ef1c G \u0111\u01b0\u1ee3c k\u1ebft n\u1ed1i v\u00e0o v\u1eadt li\u1ec7u b\u00e1n d\u1eabn P.<\/span><\/p>\n

Th\u00f4ng l\u1ed9 (k\u00eanh) l\u00e0 \u0111\u1ec3 ch\u1ec9 v\u00f9ng b\u00e1n d\u1eabn gi\u1eefa D v\u00e0 S.<\/span><\/p>\n

\"C\u1ea5u
C\u1ea5u t\u1ea1o c\u1ee7a JFET<\/span><\/figcaption><\/figure>\n

Ph\u1ee5 thu\u1ed9c v\u00e0o lo\u1ea1i b\u00e1n d\u1eabn gi\u1eefa D v\u00e0 S m\u00e0 ng\u01b0\u1eddi ta chia JFET ra th\u00e0nh JFET k\u00eanh N v\u00e0 JFET k\u00eanh P (JFET k\u00eanh N th\u01b0\u1eddng th\u00f4ng d\u1ee5ng h\u01a1n).<\/span><\/p>\n

K\u00fd hi\u1ec7u c\u1ee7a JFET<\/strong><\/span><\/h2>\n
\"K\u00fd
K\u00fd hi\u1ec7u c\u1ee7a JFET<\/span><\/figcaption><\/figure>\n

Nguy\u00ean l\u00fd ho\u1ea1t \u0111\u1ed9ng c\u1ee7a JFET<\/strong><\/span><\/h2>\n

\u0110\u1ea7u ti\u00ean, ta \u0111\u1eb7t m\u1ed9t \u0111i\u1ec7n \u00e1p VDS v\u00e0o gi\u1eefa D v\u00e0 S. Khi \u0111\u00f3, n\u00f3 s\u1ebd t\u1ea1o ra m\u1ed9t \u0111i\u1ec7n tr\u01b0\u1eddng t\u00e1c d\u1ee5ng l\u00ean h\u1ea1t t\u1ea3i \u0111a s\u1ed1 c\u1ee7a k\u00eanh b\u00e1n d\u1eabn l\u00e0m ch\u00fang ch\u1ea1y t\u1eeb S sang D v\u00e0 h\u00ecnh th\u00e0nh d\u00f2ng \u0111i\u1ec7n ID. Sau \u0111\u00f3, d\u00f2ng \u0111i\u1ec7n ID s\u1ebd t\u0103ng theo \u0111i\u1ec7n \u00e1p VDS cho \u0111\u1ebfn khi \u0111\u1ea1t gi\u00e1 tr\u1ecb b\u00e3o h\u00f2a IDSS v\u1edbi m\u1ee9c \u0111i\u1ec7n \u00e1p \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u0111i\u1ec7n \u00e1p th\u1eaft k\u00eanh VPO, t\u0103ng VDS l\u1edbn h\u01a1n VPO th\u00ec ID v\u1eabn kh\u00f4ng t\u0103ng.<\/span><\/p>\n

Ti\u1ebfp theo, ta \u0111\u1eb7t m\u1ed9t \u0111i\u1ec7n \u00e1p VGS v\u00e0o gi\u1eefa G v\u00e0 S sao cho kh\u00f4ng ph\u00e2n c\u1ef1c ho\u1eb7c ph\u00e2n c\u1ef1c ngh\u1ecbch m\u1ed1i P – N. Trong tr\u01b0\u1eddng h\u1ee3p m\u1ed1i P – N kh\u00f4ng ph\u00e2n c\u1ef1c th\u00ec ta c\u00f3 d\u00f2ng ID \u0111\u1ea1t gi\u00e1 tr\u1ecb l\u1edbn nh\u1ea5t IDSS. C\u00f2n \u0111\u1ed1i v\u1edbi tr\u01b0\u1eddng h\u1ee3p \u0111i\u1ec7n \u00e1p ph\u00e2n c\u1ef1c ngh\u1ecbch c\u00e0ng l\u1edbn th\u00ec v\u00f9ng ti\u1ebfp x\u00fac (V\u00f9ng hi\u1ebfm) c\u00e0ng m\u1edf r\u1ed9ng ra. Vi\u1ec7c n\u00e0y khi\u1ebfn ti\u1ebft di\u1ec7n c\u1ee7a k\u00eanh d\u1eabn b\u1ecb thu h\u1eb9p l\u1ea1i. K\u1ebft qu\u1ea3 l\u00e0 khi \u0111i\u1ec7n tr\u1edf k\u00eanh\u00a0 t\u0103ng l\u00ean th\u00ec d\u00f2ng \u0111i\u1ec7n qua k\u00eanh ID gi\u1ea3m xu\u1ed1ng v\u00e0 ng\u01b0\u1ee3c l\u1ea1i, VGS t\u0103ng \u0111\u1ebfn gi\u00e1 tr\u1ecb VPO th\u00ec ID gi\u1ea3m v\u1ec1 0.<\/span><\/p>\n

3 c\u00e1ch m\u1eafc c\u01a1 b\u1ea3n c\u1ee7a JFET<\/strong><\/span><\/h2>\n

JFET m\u1eafc ki\u1ec3u c\u1ef1c ngu\u1ed3n chung (Common Source = CS)<\/span><\/h3>\n

T\u00edn hi\u1ec7u v\u00e0o G so v\u1edbi S, t\u00edn hi\u1ec7u ra D so v\u1edbi S.<\/span><\/p>\n

\"JFET
JFET m\u1eafc ki\u1ec3u c\u1ef1c ngu\u1ed3n chung<\/span><\/figcaption><\/figure>\n

JFET m\u1eafc ki\u1ec3u c\u1ef1c c\u1ed5ng chung (Common Gate = CG)\u00a0<\/span><\/h3>\n

T\u00edn hi\u1ec7u v\u00e0o S so v\u1edbi G, t\u00edn hi\u1ec7u ra D so v\u1edbi G.<\/span><\/p>\n

\"JFET
JFET m\u1eafc ki\u1ec3u c\u1ef1c c\u1ed5ng chung<\/span><\/figcaption><\/figure>\n

JFET m\u1eafc ki\u1ec3u c\u1ef1c tho\u00e1t chung (Common Drain = CD)<\/span><\/h3>\n

T\u00edn hi\u1ec7u v\u00e0o G so v\u1edbi D, t\u00edn hi\u1ec7u ra S so v\u1edbi D.\u00a0<\/span><\/p>\n

\"JFET
JFET m\u1eafc ki\u1ec3u c\u1ef1c tho\u00e1t chung<\/span><\/figcaption><\/figure>\n

So s\u00e1nh JFET v\u00e0 MOSFET<\/h2>\n

N\u1ebfu b\u1ea1n ch\u01b0a bi\u1ebft c\u00e1ch ph\u00e2n bi\u1ec7t JFET v\u00e0 MOSFET th\u00ec h\u00e3y tham kh\u1ea3o ngay b\u1ea3ng b\u00ean d\u01b0\u1edbi.<\/p>\n

\n
\n
\n
\n\n\n\n\n\n\n\n\n\n\n\n
\u0110\u1eb7c \u0111i\u1ec3m<\/th>\nJFET<\/th>\nMOSFET<\/th>\n<\/tr>\n
Kh\u00e1i ni\u1ec7m<\/strong><\/td>\nTransistor c\u00f3\u00a0ba c\u1ef1c<\/td>\nTransistor c\u00f3\u00a0b\u1ed1n c\u1ef1c<\/td>\n<\/tr>\n
C\u01a1 ch\u1ebf ho\u1ea1t \u0111\u1ed9ng<\/strong><\/td>\nD\u00f2ng \u0111i\u1ec7n \u0111\u01b0\u1ee3c \u0111i\u1ec1u khi\u1ec3n b\u1eb1ng \u0111i\u1ec7n tr\u01b0\u1eddng m\u00e0 kh\u00f4ng c\u1ea7n ti\u1ebfp x\u00fac tr\u1ef1c ti\u1ebfp<\/td>\nD\u00f2ng \u0111i\u1ec7n \u0111\u01b0\u1ee3c \u0111i\u1ec1u khi\u1ec3n b\u1eb1ng \u0111i\u1ec7n tr\u01b0\u1eddng th\u00f4ng qua l\u1edbp c\u00e1ch \u0111i\u1ec7n<\/td>\n<\/tr>\n
Ch\u1ebf \u0111\u1ed9 ho\u1ea1t \u0111\u1ed9ng<\/strong><\/td>\nHo\u1ea1t \u0111\u1ed9ng \u1edf ch\u1ebf \u0111\u1ed9 khuy\u1ebft l\u1eadp (depletion mode)<\/td>\nHo\u1ea1t \u0111\u1ed9ng \u1edf c\u1ea3 ch\u1ebf \u0111\u1ed9 khuy\u1ebft l\u1eadp v\u00e0 t\u0103ng c\u01b0\u1eddng (enhancement mode)<\/td>\n<\/tr>\n
Tr\u1edf kh\u00e1ng \u0111\u1ea7u v\u00e0o<\/strong><\/td>\nCao<\/td>\nR\u1ea5t cao<\/td>\n<\/tr>\n
R\u00f2 r\u1ec9 d\u00f2ng \u0111i\u1ec7n<\/strong><\/td>\nKho\u1ea3ng 10^-9 A<\/td>\nKho\u1ea3ng 10^-12 A<\/td>\n<\/tr>\n
Thi\u1ec7t h\u1ea1i \u0111i\u1ec7n tr\u1edf<\/strong><\/td>\n\u00cdt nh\u1ea1y c\u1ea3m v\u1edbi ESD<\/td>\nD\u1ec5 b\u1ecb h\u1ecfng do ESD<\/td>\n<\/tr>\n
Chi ph\u00ed s\u1ea3n xu\u1ea5t<\/strong><\/td>\nTh\u1ea5p<\/td>\nCao<\/td>\n<\/tr>\n
\u1ee8ng d\u1ee5ng<\/strong><\/td>\nC\u00f4ng t\u1eafc \u0111i\u1ec7n t\u1eed, b\u1ed9 khu\u1ebfch \u0111\u1ea1i \u0111\u1ec7m, m\u1ea1ch c\u00f3 \u0111\u1ed9 nhi\u1ec5u th\u1ea5p<\/td>\nChuy\u1ec3n m\u1ea1ch, khu\u1ebfch \u0111\u1ea1i t\u00edn hi\u1ec7u, \u0111i\u1ec1u khi\u1ec3n \u0111\u1ed9ng c\u01a1, h\u1ec7 th\u1ed1ng nh\u00fang, m\u1ea1ch c\u00f3 \u0111\u1ed9 nhi\u1ec5u cao<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

Tr\u00ean \u0111\u00e2y l\u00e0 chia s\u1ebb c\u1ee7a H\u1ecdc vi\u1ec7n iT.vn v\u1ec1 JFET. Hy v\u1ecdng nh\u1eefng ki\u1ebfn th\u1ee9c n\u00e0y c\u00f3 th\u1ec3 gi\u00fap \u00edch cho b\u1ea1n trong qu\u00e1 tr\u00ecnh h\u1ecdc t\u1eadp v\u00e0 l\u00e0m vi\u1ec7c. N\u1ebfu c\u00f3 b\u1ea5t c\u1ee9 th\u1eafc m\u1eafc n\u00e0o th\u00ec h\u00e3y \u0111\u1ec3 l\u1ea1i b\u00ecnh lu\u1eadn ngay d\u01b0\u1edbi b\u00e0i vi\u1ebft n\u00e0y ho\u1eb7c inbox tr\u1ef1c ti\u1ebfp cho HOCVIENiT.vn \u0111\u1ec3 \u0111\u01b0\u1ee3c gi\u1ea3i \u0111\u00e1p t\u1ed1t nh\u1ea5t. Ch\u00fac b\u1ea1n th\u00e0nh c\u00f4ng!<\/span><\/p>\n

T\u00ecm hi\u1ec3u th\u00eam:\u00a0T\u1ed5ng h\u1ee3p ki\u1ebfn th\u1ee9c c\u01a1 b\u1ea3n v\u1ec1 Transistor – \u0110i\u1ec7n t\u1eed c\u01a1 b\u1ea3n<\/a><\/span><\/p>\n

M\u1ecdi chi ti\u1ebft xin vui l\u00f2ng li\u00ean h\u1ec7:
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 <\/p>\n","protected":false},"excerpt":{"rendered":"

FET \u0111\u01b0\u1ee3c chia ra th\u00e0nh JFET v\u00e0 MOSFET. Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang ta s\u1ebd c\u00f9ng t\u00ecm hi\u1ec3u v\u1ec1 JFET l\u00e0 g\u00ec? C\u1ea5u t\u1ea1o v\u00e0 k\u00fd hi\u1ec7u c\u1ee7a JFET c\u0169ng nh\u01b0 nguy\u00ean l\u00fd ho\u1ea1t \u0111\u1ed9ng c\u1ee7a n\u00f3 nh\u00e9.<\/p>\n","protected":false},"author":95,"featured_media":18524,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[734],"tags":[666],"_links":{"self":[{"href":"https:\/\/hocvienit.vn\/index.php?rest_route=\/wp\/v2\/posts\/18517"}],"collection":[{"href":"https:\/\/hocvienit.vn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hocvienit.vn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hocvienit.vn\/index.php?rest_route=\/wp\/v2\/users\/95"}],"replies":[{"embeddable":true,"href":"https:\/\/hocvienit.vn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=18517"}],"version-history":[{"count":0,"href":"https:\/\/hocvienit.vn\/index.php?rest_route=\/wp\/v2\/posts\/18517\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hocvienit.vn\/index.php?rest_route=\/wp\/v2\/media\/18524"}],"wp:attachment":[{"href":"https:\/\/hocvienit.vn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=18517"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hocvienit.vn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=18517"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hocvienit.vn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=18517"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}