555 Timer, Astable (Freq/Duty Cycle In, Rt/Rb/C Out)
This calculator calculates the resistances and capacitances needed to operate a 555 timer in astable mode. The duty cycle cannot be set lower than 50%, if you want to do this you will have to attach an inverter to the output.
| Frequency | The desired frequency of the 555 output waveform. | ||
| Duty Cycle | The desired duty cycle. Because of the design of the 555, the duty cycle must be greater than 50%. | ||
| Capacitance | The capacitance of the capacitor connected to the 555. | ||
| Period | |||
| Time High | |||
| Time Low | |||
| R1 | |||
| R2 |