Next, this module will look at the effect of the applied voltage on the capacitance of the SIDACtor. The graph shown here is for a popular C rated 260V SIDACtor. With no voltage applied, the capacitance is quite high compared with the capacitance with just a few volts applied. Other SIDACtor devices will have higher or lower capacitance, but they all follow the same basic curve. In telephone voice circuits, this has no real effect. However, in data circuits this characteristic can cause data errors. This is why Littelfuse developed the MC line of SIDACtor devices. These devices have significantly less capacitance than the standard line and are ideal in applications such as T1/E1, ADSL and ISDN. For very high speed data circuits such as VDSL or Ethernet, Littelfuse recommends biased bridge technology devices. These are the SDP and SEP protectors and are specifically designed to eliminate this capacitance issue.