555 Timer Calculator - Frequency and Duty Cycle

IC 555 Timer Calculator

Enter value and click on calculate. Result will be displayed.

Enter values for R1, R2, and C and press the calculate button to solve for positive time interval (T1) and negative time interval (T2). For example, a 10K resistor (R1) and 100K (R2) and 0.1 uF capacitor will produce output time intervals of 7.62 ms positive (T1) and 6.93 ms negative (T2). The frequency will be about 70 Hz. R1 should be greater than 1K and C1 should be greater than .0005 uF.

Positive Time Interval (T1) = 0.693 * (R1+R2) * C1
Negative Time Interval (T2) = 0.693 * R2 * C1
Frequency = 1.44 / ( (R1+2R2) * C1)

Enter Your Values
Resistance R1:	K Ohms
Resistance R2:	K Ohms
Capacitance C1:	Microfarads
Result
Positive Time Interval T1 :	ms
Negative Time Interval T2:	ms
Frequency:	KHz