This circuit is designed around an RC network that produces a slow input to the second inverter. The RC time constant, τ, is calculated from: τ = RC.

The delay time for this circuit is from t_delay(min) = –ln |1 – V_T+(min) / V_CC| τ to t_delay(max) = –ln |1 – V_T+(max) / V_CC| τ. It must be noted that the delay is consistent for each device, but because the switching threshold is only ensured between the minimum and maximum value, the output pulse length varies between devices. These values must be calculated by using the minimum and maximum V_T+ values in the Electrical Characteristics.

The resistor value must be chosen such that the maximum current to and from the SN74AHC14 is 8 mA at
5-V V_CC.