Yes. Electric potential can be negative because voltage is defined relative to a chosen zero. A point at negative 12 volts is simply 12 volts below the reference point.
Negative potential is not the same as negative charge, and it does not automatically mean negative potential energy. The charge sign matters because electric potential energy is U = qV.
Why electric potential can be negative
Electric potential measures potential energy per unit positive test charge. Its unit is the volt, equal to one joule per coulomb.
For an isolated point charge, choosing zero potential at infinity gives:
V = kQ ÷ r
The potential is positive near a positive source charge and negative near a negative source charge. With several charges, scalar potentials add algebraically.
Potential versus potential energy
Potential, V, describes the field at a location. Potential energy, U, belongs to a charge in that field:
U = qV
- A positive charge at negative potential has negative potential energy.
- A negative charge at negative potential has positive potential energy.
- Opposite source charges can form a bound system with negative potential energy when zero is chosen at infinite separation.
Only potential differences are measurable
A voltmeter compares two points. It does not measure an absolute voltage independent of a reference.
In circuit diagrams, “ground” is often assigned 0 V for convenience. A negative supply rail is below that reference, but a different reference choice can shift every labeled potential without changing circuit behavior.
Where is potential highest and lowest in a circuit?
That depends on the selected reference and source polarity. Across an ideal resistor, conventional current flows from higher potential to lower potential. Across a power source, internal forces raise charge from lower to higher potential.
Real conductors have voltage drop, and rapidly changing circuits can include inductive and capacitive effects. Use Kirchhoff’s laws with consistent polarity labels.
Is there a minimum or maximum potential?
There is no universal minimum or maximum electric potential. In the ideal point-charge model, magnitude grows without bound as distance approaches zero.
Real charges occupy finite structures, and breakdown, field emission, material limits and geometry constrain achievable voltages. The practical maximum or minimum therefore belongs to a specified physical system and reference.
Two quick examples
Battery terminals: If the negative terminal of a 12.6-volt battery is defined as 0 V, the positive terminal is +12.6 V. If the positive terminal is instead defined as 0 V, the negative terminal is -12.6 V. The labels change, but the 12.6-volt potential difference does not.
A negative source charge: For a point charge, V = kQ/r when zero potential is chosen at infinity. A negative Q therefore produces negative potential. A positive test charge at that location has negative potential energy, while an electron has positive potential energy because both q and V are negative. As OpenStax explains, the zero point is arbitrary and the measurable quantity is the potential difference.
Sources