This report describes a laboratory testbench designed for testing of electronic ballasts of LED lams. Possible configurations of such testbench are compared and the most suitable one is discussed in details. The paper also deals with fluent lighting regulation mode ballasts build as buck and buck/boost choppers. Their efficiency, as well as linearity and resolution of light regulation are compared. The conclusion that frequency modulated buck dimmer used as a part of electronic ballast provides better efficiency and is more controllable.