Electronics
Drop as a percentage
Converts the absolute drop into the form regulations are written in, so a single limit applies at any supply voltage.
The Formula
percent = V_drop / V_supply x 100
Converts the absolute drop into the form regulations are written in, so a single limit applies at any supply voltage.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| V_drop | Voltage drop | volts | The loss computed from length, current and resistance. |
| V_supply | Nominal supply voltage | volts | 230 volts for a typical single-phase supply. |
| pct | Percentage drop | percent | Usually limited to a few percent of the supply. |
What Each Symbol Means
V_dropvolts
Voltage drop
The loss computed from length, current and resistance.
V_supplyvolts
Nominal supply voltage
230 volts for a typical single-phase supply.
pctpercent
Percentage drop
Usually limited to a few percent of the supply.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate voltage drop page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Voltage Drop, filed under Science. Every number the guide produces comes from substituting into this one line.