Electrical engineering
Direct current
Ohm's law, power, energy and resistor networks.
Electrical engineering
Ohm's law
U = I × R→Electrical engineeringElectric power
P = U × I→Electrical engineeringCurrent from Ohm's law
I = U / R→Electrical engineeringResistance from Ohm's law
R = U / I→Electrical engineeringSeries resistance
R = R₁ + R₂ + R₃→Electrical engineeringParallel resistance
R = R₁R₂ / (R₁ + R₂)→Electrical engineeringElectric energy
W = Pt→Electrical engineeringElectric charge
q = It→Electrical engineeringCapacitor energy
W = CU² / 2→Electrical engineeringSource terminal voltage
U = ε − Ir→Electrical engineeringElectric current work
A = UIt→Electrical engineeringTwo resistors in series
R = R₁ + R₂→Electrical engineeringPower from current and resistance
P = I²R→Electrical engineeringPower from voltage and resistance
P = U²/R→Electrical engineeringSource efficiency
η = R/(R+r) × 100%→Electrical engineeringDifferential Ohm's law
j = σE→Electrical engineeringThree resistors in parallel
R = 1/(1/R₁+1/R₂+1/R₃)→