Power supply requirements for LED lamps or lighting modules, such as our MR16 LED downlight replacement globes, can vary considerably and it is essential that a suitable power supply is used. Switchmode transformers, or electronic transformers that are designed to run halogen lights, should not be used with LED lighting modules or lamps unless they are specifically certified to do so. LED lamps are compatible with all types of magnetic (linear)transformers, but not all types of switchmode transformers. Most halogen lamp switchmode transformers require a minimum load to function correctly & output a high frequency pulse train based on the load requirements. As LED lamps draw a fraction of the current of an equivalent halogen lamp (typically ~1/10th), this usually results in problems such as flickering, strobing, or in some cases, no light at all. It may also reduce the life expectancy of the LED lamp. It is essential the maximum input voltage of the LED lamp or module is not exceeded and the power supply can deliver the necessary current required in a linear manner. If using switchmode or electronic power supplies, make sure they are designed for use with LED lamps, otherwise use a linear power supply or a DC output power supply.