Efficiency Total⚠ unverified
Electrical / Power Electronics · Compute the overall efficiency from output power and total losses
Parameters
| Input | Symbol | Unit | Default | Description |
|---|---|---|---|---|
| Pout | Pout | W | 1.0 | Output power |
| Plosses | Plosses | W | 1.0 | Total power losses |
| Output | Symbol | Unit | Description |
|---|---|---|---|
| result | η | — | Efficiency (dimensionless), in the range 0 to 1. Returns 0.0 when the total input power is not positive |
The science & history
Understanding the Parameters
- $P_{out}$ — average power into the load ($V_{out} I_{out}$ for DC, or real power for AC).
-
$P_{losses}$ — every watt that becomes heat or other non-load energy: FET conduction and switching, diode forward, gate drive, magnetics core and copper, snubbers, quiescent bias, etc. Underestimating $P_{losses}$ overstates $\eta$.
-
$\eta$ — fraction of input energy that reaches the load. Power dissipated as heat is $P_{heat} = P_{losses} = P_{out}(1/\eta - 1)$.
Derivation (Approaching a Proof)
In steady state, energy conservation for a converter with no net stored-energy change requires
$$P_{in} = P_{out} + P_{losses}.$$
Efficiency is defined as the ratio of useful output to total input:
$$\eta \equiv \frac{P_{out}}{P_{in}} = \frac{P_{out}}{P_{out} + P_{losses}}.$$
No circuit assumptions enter beyond power balance. Component-level calculators (Conduction Loss, Switching Loss, Gate Drive Power, Core Loss Steinmetz, Diode Forward Loss, …) supply the pieces of $P_{losses}$.
Example: $P_{out} = 100\,\text{W}$, $P_{losses} = 5\,\text{W}$ → $\eta = 100/105 \approx 0.952$ (95.2%), heat = 5 W.
History
Efficiency has been the headline metric for power supplies since linear regulators were displaced by switchers. Regulatory programs (80 PLUS, ErP, DoE) and thermal limits make accurate loss summation — and this total $\eta$ — a standard design checkpoint.
Related Concepts: Conduction Loss, Switching Loss, Gate Drive Power, Core Loss Steinmetz, Diode Forward Loss, Watt's Law
Notes: Registry calculator efficiency-total (unverified). Definitional; quality of $\eta$ is only
as good as the loss inventory. Output is a fraction, not percent.