NE555 Astable Calculator
Calculate approximate astable frequency and waveform duty cycle from timing resistors and capacitor using the TI NE555 datasheet relationships.
A QUICK WALKTHROUGH
How to use this tool
- Enter values in the displayed SI units.
- Review the assumptions and formula.
- Calculate locally; verify all design values independently.
Formula and limits
T≈0.693(RA+2RB)C; f≈1.44/((RA+2RB)C); waveform duty≈(RA+RB)/(RA+2RB). Formula: https://www.ti.com/lit/ds/symlink/ne555.pdf This is a simplified estimate and does not validate component ratings, safety, or process quality.
Privacy
Inputs are calculated locally and are not uploaded.
GOOD TO KNOW
Common questions
Does this validate a design or casting process?
No. It evaluates the stated model only.