| Symbols | Definitions |
| C | Capacitance |
| Q | electric charge |
| R | universal gas constant |
| T | temperature |
| z | ion valency |
| F | Faraday constant |
| Em | membrane potential |
| PK | potassium permeability |
| e | elementary charge = 1.602, 176, 634 × 10−19 C |