Key parameters for the PLED are V_BR, I_S, I_H, I_T, and
V_T, as shown in the V-I curve. V_BR is the region from
the off-state voltage to breakdown voltage rating
of the device. In the off-state, V_BR is the continuous
peak combination of ac and dc voltage that may be
applied to the device with less than 5 μA conducted
through it. I_S is the value of current that makes
the device switch from the off to on-state when a
minimum V_BR is applied. Holding current (I_H) is the
minimum current needed to maintain the device in
the on state. On-state voltage (V_T) is the maximum
voltage across the device during full conduction. I_T
is the maximum rated current the device can carry
during the on-state for 2 sec.