The 74HC14 is one of the most versatile integrated circuits (ICs) in a hardware designer's toolkit. While officially designated as a hex inverter with Schmitt trigger inputs, it is widely used to create simple, low-cost, and reliable relaxation oscillators.
The inverter responds by pulling the output LOW (
So for α=0.6, β=0.4: f ≈ 1.233 / (R·C). This is a useful rule of thumb. 74hc14 oscillator calculator full
The frequency of oscillation is determined by the RC time constant and the hysteresis thresholds of the Schmitt trigger.
R≈110-4cap R is approximately equal to the fraction with numerator 1 and denominator 10 to the negative 4 power end-fraction The 74HC14 is one of the most versatile
is a constant, usually between 0.8 and 1.2, depending on the supply voltage ( VCCcap V sub cap C cap C end-sub ) and the specific manufacturer of the 74HC14. The "Full" Formula For a more precise, standard design (assuming
, the IC output stage will struggle to supply or sink enough current to charge the capacitor effectively. If is higher than This is a useful rule of thumb
), the constant k is often taken as ≈ 1.0, simplifying the formula to:
+---|>---o-- Output | | ----+ | | _|_ | _)_ C (Capacitor) R| | | | ----+----+ | GND
The frequency is somewhat dependent on supply voltage.