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# Rise time

In electronics, rise time usually refers to the time it takes for a voltage to rise from 10% to 90% of its peak value. Rise time (also risetime) values in a resistive circuit are primarily due to stray capacitance and inductance in the circuit. Due to differences in driving circuit power, rise time may or may not be equal to fall time.

In control theory, it is often defined as the 10% to 90% time from a former setpoint to new setpoint. The quadratic approximation for normalized rise time for a 2nd-order system, step response, no zeros is:

tr = 2.230n2 - 0.078n + 1.12 where n=damping ratio
03-10-2013 05:06:04