Skip to main content

Formulas

Current (I) (amps)

Parallel IT = I1 + I2 + I3

Ohms law

I = V/Ω

Individual current of resistor (Series)

IT = I1 = I2 = I3

Individual current of resistor (Parallel)

(Total resistance / individual resistance) x total circuit current

Voltage (V) (Volts)

Voltage drop across each resistor V = I x R
Voltage across resistros in a circuit (Parallel) VT = V1 = V2

Power (W) (Watts)

Power dissipated by a resistor P = I x V
Power dissipated by a resistor P = Ix Ω
Power dissipated by a resistor P = V2 / Ω


Resistance (Ω) (Ohms)

Resistance with multiple resistors (Parallel) Ω = (R1-1 + R2-1 + R3-1) -1
Resistance with multiple resistors (Seiries) Ω = R1 + R2 + R3
Ohms law Ω = V / I
Resistivity resistivity x length (m) / cross sectional area
Resistance at certain temprature Resistor 1 resitance x (1 + resistance at temprature x (temp 1 - temp 2)

Time constant  (τ) (Tou)

1 time constant τ = Capacitance x Resistance