This document deals with class Φ inverter whose structure is at the origin class Φ2 and EF 2 inverters. A tuning methodology is exposed and experimental demonstration of a 15 MHz -25 W inverter is performed. The load resistor is then removed from its nominal value and the impact of this operation on the inverter's behavior is investigate. Experimental findings reveal that altering the load resistance induces a loss of Zero Voltage Switching (ZVS) or Zero derivative Voltage Switching (ZdVS), contingent upon whether the inverter is overloaded or underloaded. Furthermore, experimental results indicate the potential occurrence of reverse conduction in the switch, which could significantly impede the converter's overall performance. Notably, the measured efficiency demonstrates that superior performance is attainable by employing load resistance values higher than the nominal value, as opposed to lower values.