555 Timer Astable Calculator (Frequency, Duty Cycle)

555 Timer Astable Mode Calculator

555 Timer Pinout:

Standard 8-pin 555 timer IC pinout.

Resistor R1:

Resistor R2:

Capacitor C1:

Formulas Used:

Time High (T_h) = 0.693 × (R1 + R2) × C1

Time Low (T_l) = 0.693 × R2 × C1

Period (T) = T_h + T_l

Frequency (f) = 1 / T = 1.44 / ((R1 + 2 × R2) × C1)

Duty Cycle (%) = (T_h / T) × 100

Note: R1 and R2 are in Ohms (Ω), C1 is in Farads (F).