A net negative charge is used to eliminate silver migration in an EL lamp.
An electrode containing silver, either the entire electrode, a bus bar on
the electrode, or a contact area on the electrode, receives a net
negative charge while the EL lamp is being driven with alternating
current. The net negative charge can be provided by the driver itself or
by a current source, such as a battery or a charged capacitor; or by
asymmetric current means in the current path of the EL lamp, including
the lamp itself.