555 Timer Monostable Mode
In monostable (one-shot) mode, the 555 timer outputs a single HIGH pulse of a precisely defined duration when triggered. It then returns to LOW and waits for the next trigger. Used in button debouncing, pulse generation, missing pulse detection, and timed relay activation.
One-shot pulse
Pulse width T1.100 s
FormulaT = 1.1 × R × C
Formulas used
Pulse Width: T = 1.1 × R × C
How to use this calculator
Step-by-Step Instructions
- Enter the timing resistor R Connected between VCC and pins 6/7 of the 555. This, along with C, determines pulse duration.
- Enter the timing capacitor C Connected between pin 6 and ground. Larger values give longer pulses.
- Click Calculate The output pulse width is displayed in seconds, milliseconds, or microseconds as appropriate.
Worked Example 1 Second Pulse
R = 910kΩ, C = 1µF T = 1.1 × 910000 × 0.000001 = 1.001 seconds