Supply units for providing a high-frequency RF voltage and an RF current to electrosurgical instruments so that they can be used for cutting and/or coagulating tissue, while providing regulation of the RF current and the RF voltage and providing a corresponding feedback for the treating physician. A supply unit includes an RF generator unit for generating the RF output voltage, a measuring unit for determining an electrical load while an RF output current is being applied, a signal unit for outputting a haptically perceivable (e.g., tactile) signal and a control unit that is in communicative connection at least with the measuring unit and the signal unit to activate the signal unit as a function of the electrical load.