Heuristic: 1010.10 Hz Exact (5V): 964.32 Hz
period = 1 / freq return freq, period r = 18e3 # 18k ohm c = 100e-9 # 100 nF 74hc14 oscillator calculator
import math def hc14_oscillator(r_ohms, c_farads, v_cc=5.0, method="heuristic"): """ Calculate frequency and period for a 74HC14 RC oscillator. method: "heuristic" (0.55 constant) or "exact" (with thresholds) """ if method == "heuristic": freq = 1 / (0.55 * r_ohms * c_farads) else: # exact for 5V typical thresholds v_tplus = 3.15 # Typical at 25C, 5V v_tminus = 1.85 num = v_tplus * (v_cc - v_tminus) den = v_tminus * (v_cc - v_tplus) freq = 1 / (r_ohms * c_farads * math.log(num / den)) Heuristic: 1010
A would do all this in 0.2 seconds and optionally plot the waveform. Part 6: Advanced Calculators – Including Hysteresis For engineers requiring precise duty cycle control, you need an advanced calculator that uses the actual hysteresis window. 413 k$\Omega$ is within the acceptable range (below 1M)
413 k$\Omega$ is within the acceptable range (below 1M). However, a common 5% value is 390 k$\Omega$ or 430 k$\Omega$. Use 430 k$\Omega$.