Electrical engineering formula sheet
| Formula | Equation | Symbols | Conditions |
|---|---|---|---|
| DC Circuits | |||
| Ohm's Law | V = IR | V Voltage (V); I Current (A); R Resistance (Ω) | Ohmic material at constant temperature |
| Electrical Power (V×I) | P = VI | P Power (W); V Voltage (V); I Current (A) | DC or instantaneous values |
| Electrical Power (I²R) | P = I²R | P Power (W); I Current (A); R Resistance (Ω) | Resistive element; DC or RMS for sinusoidal AC |
| Resistors in Series 1 | R_total = R₁ + R₂ | Rₜₒₜₐₗ Total Resistance (Ω); R₁ Resistance 1 (Ω); R₂ Resistance 2 (Ω) | not defined |
| Resistors in Parallel 1 | 1 / (R_total) = 1 / R₁ + 1 / R₂ | Rₜₒₜₐₗ Total Resistance (Ω); R₁ Resistance 1 (Ω); R₂ Resistance 2 (Ω) | not defined |
| Capacitance 1 | C = Q / V | C Capacitance (F); Q Charge (C); V Voltage (V) | not defined |
| Capacitor Energy 1 | E = (1/2)CV² | E Energy (J); C Capacitance (F); V Voltage (V) | not defined |
| RC Time Constant 1 | τ = RC | τ Time Constant (s); R Resistance (Ω); C Capacitance (F) | not defined |
Equations are rendered from the library's own typeset source with no term reordered, dropped or simplified. Symbol legends and validity conditions are the library's; an equation is a model, not a guarantee — confirm its assumptions hold before you rely on a result.
- The formula library records no validity conditions for this entry. An absent condition line is not a statement that the formula is unconditional — check the source before applying it outside the obvious case.
Reference values are provided for study and quick reference. Verify against current standards and manufacturer data before safety-critical design.