The 555 timer is capable of being used in astable and monostable circuits. In a monostable circuit, the output voltage becomes high for a set duration once a falling edge is detected on the trigger pin (pin 2).
![555 monostable output](/static/img/555-monostable-calculator-1.png)
![](/static/img/555-monostable-calculator-2.png)
The Output Pulse Width (T) is calculated with the following formula
T = 1.1 * R * C
Enter any two known values and press "Calculate" to solve for the others.