Ko te ture tuatahi a Kirchhoff, e kiia nei ko te ture o te pūwāhi hononga, e kī ana ko te iahiko e tomo ana ki tētahi pūwāhi hononga he rite tonu ki te iahiko e puta ana mai i taua pūwāhi hononga. Ko te pūwāhi hononga i roto i tētahi ara iahiko hiko ko te pūwāhi e tūtaki ai ngā kaiārahi e rua, neke atu rānei, pērā i te pūwāhi a i te ahua kei te taha.
Ko I te iahiko e tomo ana ki te pūwāhi hononga, ko I 1 me I 2 ia ngā iahiko e puta ana i te pūwāhi hononga, I = I 1 + I 2. Hei tauira anō, mātakitakina te ahua i raro nei.
Ko au te tangata e haere mai ana hiko hiko, i ahau1, I2, me ahau3 ko ngā iahiko e puta ana, I = I1 + Ko ahau2 + Ko ahau3.
Ko te ture tuatahi a Kirchhoff e ahu mai ana i te ture tiaki hiko e kī ana he pumau tonu te utu, me rite te utu hiko e haere mai ana ki te utu hiko e puta mai ana, kāore he utu hiko e ngaro. Ko te au hiko he utu hiko e rere ana i roto i tētahi wā. Ko te au hiko e tomo ana ki tētahi pūwāhi hononga he rite tonu ki te au hiko e puta mai ana i taua pūwāhi hononga.
Ko te ture tuatahi a Kirchhoff i whakapuakina e Gustav Kirchhoff (1824-1887), he tohunga ahupūngao Tiamana.
Tauira raruraru 1:
I1 = 2A, I2 = 3A, I3 = 5A, I4 = 3A. Whakatauhia te I5!
Rongoā:
Ka tomo ahau = Ka puta ahau
1 + 3 = 2 + 4 + 5
2 A + 5 A = 3 A + 3 A + I 5
7 A = 6 A + I 5
I 5 = 7 A – 6 A
I 5 = 1 A
Tauira raruraru 2:
I = 10 A, I1 = 2 A, I2 = 4 A. Whakatauhia te I3!
Rongoā:
Ka tomo ahau = Ka puta ahau
I = I 1 + I 2 + I 3
10 A = 2 A + 4 A + I 3
10 A = 6 A + I 3
I 3 = 10 A – 6 A
I 3 = 4 A