With a 4k1 collector resistor and 16mA drive into the led, the chosen (read ‘cheapest on ebay’) 6N135 is supposed to beat 1.5μs for both turn on and turn off, with typical figures of 90ns and 800ns.

In this unique historical context, Zeng Guofan makes resurgence of Tongcheng Group once more and influences the late Qing dynasty for half a century, letting it transform and innovate., 正是在这一独特的历史语境下， ...