555 Timer Monostable Circuit Calculator

The 555 Timer can operate in three modes: Monostable, Astable, and Bistable. This calculator focuses on the Monostable Mode, where the timer produces a single output pulse of a specific duration when triggered.

What Is Monostable Mode?

In Monostable mode, the 555 timer acts as a one-shot pulse generator. When a falling edge is detected on the Trigger pin (Pin 2), the Output pin (Pin 3) goes high for a fixed time, then returns to low. This duration is determined by a resistor (R) and a capacitor (C) connected to the circuit.

The output pulse width T is given by the formula:

T=1.1×R×C

• T = Output pulse duration (in seconds)

• 1.1: Constant derived from the internal design of the 555 timer IC

• R = Resistance in ohms (Ω)

• C = Capacitance in farads (F)

Circuit Diagram – 555 Timer Monostable Circuit Calculator

A basic monostable circuit has:

• One resistor R (connected to Pin 7 and Vcc).

• One capacitor C (connected between Pin 6 and ground).

• A trigger button that sends a short, low pulse to Pin 2.

• A pull-up resistor on the trigger pin (optional).

When the button is pressed, the trigger input detects a low pulse, and the 555 timer outputs a single high pulse of width.

How to Use the 555 Timer Monostable Circuit Calculator

1. 1. Enter Capacitor Value: Type your capacitor value and select the appropriate unit (pF, nF, μF, or mF)
   2. Enter Resistor Value: Type your resistor value and select the unit (Ω, kΩ, or MΩ)
   3. Click Calculate: The pulse width result appears instantly
   4. View the Waveform: The visualization shows exactly how your circuit will behave
   5. Reset if Needed: Clear all fields with the reset button to start over