Roinnteoir Voltais

Faigheann riail roinnteora voltais an voltas thar ualach i gciorcad leictreach, nuair a bhíonn na hualaí ceangailte i sraith.

Riail roinnteora voltais do chiorcad DC

Maidir leis an gciorcad DC le foinse voltais tairiseach V _T agus friotóirí i sraith, tugtar an titim voltais V _i friotóir R _i leis an bhfoirmle:

$V_i = V_T \: \ frac {R_i} {R_1 + R_2 + R_3 + ...}$

V _i - titim voltais sa fhriotóir R _i volta [V].

V _T - an fhoinse voltais choibhéiseach nó an titim voltais i volta [V].

R _i - friotaíocht an fhriotóra R _i in ohms [Ω].

R ₁ - friotaíocht an fhriotóra R ₁ in ohms [Ω].

R ₂ - friotaíocht an fhriotóra R ₂ in ohms [Ω].

R ₃ - friotaíocht an fhriotóra R ₃ in ohms [Ω].

Tá foinse voltais V _T = 30V ceangailte le friotóirí i sraith, R ₁ = 30Ω, R ₂ = 40Ω.

Faigh an titim voltais ar fhriotóir R ₂ .

V ₂ = V _T × R ₂ / ( R ₁ + R ₂ ) = 30V × 40Ω / (30Ω + 40Ω) = 17.14V

Maidir leis an gciorcad AC le foinse voltais V _T agus ualaí i sraith, tugtar an titim voltais V _i ualach Z _i leis an bhfoirmle:

$V_i = V_T \: \ frac {Z_i} {Z_1 + Z_2 + Z_3 + ...}$

V _i - titim voltais in ualach Z _i volta [V].

V _T - an fhoinse voltais choibhéiseach nó an titim voltais i volta [V].

Z _i - impedance an ualaigh Z _i in ohms [Ω].

Z ₁ - impedance ualach Z ₁ in ohms [Ω].

Z ₂ - impedance ualach Z ₂ in ohms [Ω].

Z ₃ - impedance ualach Z ₃ in ohms [Ω].

Tá foinse voltais V _T = 30V∟60 ° ceangailte le hualaí i sraith, Z ₁ = 30Ω∟20 °, Z ₂ = 40Ω∟-50 °.

Faigh an titim voltais in ualach Z ₁ .

V ₂ = V _T × Z ₁ / ( Z ₁ + Z ₂ )

= 30V∟60 ° × 30Ω∟20 ° / (30Ω∟20 ° + 40Ω∟-50 °)

= 30V∟60 ° × 30Ω∟20 ° / (30cos (20) + j30sin (20) + 40cos (-50) + j40sin (-50))

= 30V∟60 ° × 30Ω∟20 ° / (28.19 + j10.26 + 25.71-j30.64)

= 30V∟60 ° × 30Ω∟20 ° / (53.9-j20.38)

= 30V∟60 ° × 30Ω∟20 ° / 57.62Ω∟-20.71 °

= (30V × 30Ω / 57.62Ω) ∟ (60 ° + 20 ° + 20.71 °)

= 15.62V∟100.71 °