Startup waveform. Pulse starts almost immediately after power on, but it takes about 87 milliseconds for the DC bias to reach the full 138 V. In this process, significant ripple can be seen on the 5 V rail, suggesting DC-DC converter is operating to charge the capacitor.

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1. niconiconi (niconiconi@cybre.space)'s status on Tuesday, 25-Jan-2022 05:06:16 UTC niconiconi

   in reply to

   USB Killer waveform captured - 4 kHz inverse sawtooth wave, 622 ns rise time, 172 volts AC peak-to-peak. The sawtooth wave itself is riding on a 138 volts DC bias, giving a total peak voltage of 310 volts AC + DC. The DC bias decreases as the stored energy goes down, the pulse stops after 20 seconds.

   Unlike the original version, this particular variant uses a positive, not negative surge, and also adds a huge DC bias to the pulse. Its designer must have spent much time on improving its destructiveness. And curiously, it attacks only D-, not D+ data line, not sure if it's a manufacturing defect, or an intentional attempt to concentrate energy on a single line. #electronics