NE555 Timer Astable Circuit Calculator

NE555 Timer Astable Circuit

The NE555 timer astable circuit employs the NE555 timer IC (integrated circuit) configured as an astable multivibrator. It includes resistors, capacitors, and the NE555 timer IC arranged in a defined configuration to produce a continuous square wave output. Operating in astable mode, the NE555 timer IC continuously toggles between its high and low states without requiring external triggering.

 The primary objective of the NE555 timer astable circuit is to generate square wave signals characterized by specific frequency and duty cycle parameters. Widely utilized as a clock generator, pulse generator, oscillator, or timing circuit, it offers precise control over the frequency and duration of output pulses. This versatility renders it suitable for a diverse array of timing and control applications within the realm of electronics.

Understanding NE555 Timer Astable Circuit:

Working Principle:

The operational principle of the NE555 Timer Astable Circuit involves leveraging the built-in voltage division mechanism of the 555 timer IC to produce a square wave signal. This setup primarily comprises three essential elements: R1, R2, and C1. Capacitor C1 undergoes charging and discharging cycles facilitated by resistors R1 and R2, leading to a repetitive transition between the high and low voltage states.

Duty Cycle:

The proportion of time spent in the high and low states dictates the duty cycle of the output square wave. In Astable Circuit configurations, this duty cycle commonly hovers at approximately 50%, yet it is modifiable through alterations in the values of R1 and R2.

Circuit Diagram: The basic circuit diagram of the NE555 Timer Astable Circuit is as follows,

VCC: 5V (or 9V)

GND: Ground

R1: 1kΩ to 10kΩ

R2: 1kΩ to 10kΩ

C1: 10nF to 100μF

OUT: Output pin (pin 3)


The NE555 Timer Astable Circuit is a commonly employed circuit known for its simplicity in generating a square wave output with a defined frequency and duty cycle. Its versatility extends to numerous applications including timing circuits, oscillators, and pulse generators, making it widely utilized. Moreover, its affordability and straightforward implementation further contribute to its popularity.


“The circuit’s frequency range is restricted, potentially rendering it unsuitable for high-frequency applications. Furthermore, its usability for high-precision tasks could be compromised by the intrinsic constraints of the 555 timer IC.”


  • Pulse Generation 
  • Timing and Control 
  • Frequency Division 
  • LED Blinkers 
  • Audio Oscillators 
  • Waveform Generation


To recap, the NE555 Timer Astable Circuit represents a basic electronic setup capable of producing a square wave output characterized by a defined frequency and duty cycle. It finds extensive application across various fields and serves as an excellent introduction for novices as well as seasoned electronics aficionados.

With the NE555 timer astable circuit calculator, you can easily access key parameters including frequency, high time, low time, and duty cycle. Just enter the values of the resistors and capacitor, namely resistor1, resistor2, and capacitor, to obtain precise calculations tailored to your circuit design.

Note : Don’t end with comma ( , )

Resistor 1 (R1)
Resistor 2 (R2)
Capacitor (C)


\[d = \left(\frac{THigh}{THigh+Tlow}\right) X 100\]
\[f = \frac{1.44}{(R1+2(R2))*C}\]
\[THigh = 0.683*(R1+R2) * C\]
\[Tlow = 0.693 * R3 * C\]


  • R1 = Resistor 1
  • R2 = Resistor 2
  • C = Capacitor
  • d = Duty Cycle
  • f = Frequency
  • THigh = Time High
  • Tlow = Time Low

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