Magnetic Low Voltage (MLV) and Electronic Low Voltage (ELV) dimmers are designed to control the voltage supplied to specific types of lighting loads. MLV dimmers are intended for use with inductive loads, such as magnetic transformers found in older low-voltage halogen systems. ELV dimmers, conversely, are designed for capacitive loads, typically electronic transformers also used with low-voltage halogen setups. A mismatch between the dimmer type and the load characteristics can cause flickering, buzzing, reduced lamp life, or even damage to the dimmer itself. The underlying impedance is the main culprit here, since it changes the electrical current.
The incompatibility stems from the operational differences between traditional incandescent/halogen bulbs and light-emitting diodes (LEDs). Incandescent and halogen bulbs present a relatively stable and predictable resistance, allowing MLV and ELV dimmers to accurately control their brightness. LEDs, however, are semiconductor devices that require a constant current to operate correctly. Their impedance characteristics are very different, behaving more like a diode with a non-linear current draw. Traditional dimming methods designed for resistive loads are not effective with the complex electrical properties of LEDs. This electrical distinction renders direct compatibility challenging without appropriate modifications or specific driver circuitry.
