On Tuesday, August 11, 2020 at 6:45:05 AM UTC-7, wrote:
At 11:23 11 August 2020, s6 wrote:
If I remember ok it is the time it takes to reach 80% of the
thermal strength.

Actually (1− 1/e) (approximately 63 percent)
J.
Also, the time constant of the electronics is after mechanical lags, so the delay may be somewhat longer.