Astable formulas: t1 (output high) = 0.693×(R_A+R_B)×C, t2 (output low) = 0.693×R_B×C, period T = t1+t2, frequency f = 1/T, duty cycle = t1/T. In this standard configuration duty cycle is always >50% (output is high longer than low) since t1 always includes both R_A and R_B while t2 only includes R_B. Monostable formula: pulse width t = 1.1×R×C, triggered by a falling edge on the trigger pin, independent of R_A/R_B.