Magnetically Regulated (Mag Reg) and Regulated Lag (Reg Lag) are another type of EM (Electromagnetic Ballasts) HID ballasts. This ballast design is the most sophisticated and provides the highest power regulation to the lamp. They utilize a magnetic with three separate coils. A ballast incorporating this circuit consists of three coils instead of the usual two or one, with the third coil and its capacitor stabilizing the lamp. One coil connects to a capacitor for increased Power Factor and to regulate current into the lamp coil.
The lamp coil is isolated from the power supply. This circuit provides very good control over light output. In some ballast designs, large changes in voltage cause very small changes in lamp wattage. A typical CCF range for magnetically regulated ballasts is 1.4 to 1.6. They are rated to handle supply voltage variations of 10% or higher, which results in approximately 5% lamp power variation. The following schematic shows the Magnetic Regulator (Regulated Lag) HID Ballast Circuit Diagram. This circuit can operate at a variety of line voltages by using the different Line V transformer tap locations.