Other real world application issues arise when the discussion involves the phrase turn on time. This presentation has shown at least three different, and yet valid, aspects of turn on time as it relates to the circuit. This scope trace shows the voltage across a 170V SIDACtor when a 100A, 10 x 1000 surge waveform is applied. The time scale is 500ns or half a microsecond per each of the ten divisions so that the entire picture is five microseconds wide. The voltage is 50V per division so that this waveform peaks very near the 170V rating of the part. Consider the time it takes to clamp the surge waveform. This graph shows that once the voltage achieves the 170V level, the SIDACtor is immediately clamping. This means that, at least on this time scale, the part clamps the surge waveform instantly. This is how we can claim that the SIDACtor turns on in nanoseconds. As can be seen, once the voltage is clamped, the voltage begins to fall after about 400ns. This is typical of SIDACtor devices. Finally, notice the rather slow and graceful transition into the crowbar state. This has some advantages over other technologies. Gas discharge tubes, for instance, transition very quickly to their on state. This can cause excessive noise on customer circuits during a surge event, especially those that utilize blocking capacitors.