Simple 555 Timer IC Math Calculation in Astable Mode:
In the given circuit, the values of the components are:
- R1 = 1K (1000 Ohms)
- R2 = 100K (100,000 Ohms)
- C1 = 10uF (0.00001 Farads)
Let’s calculate the key time parameters for the 555 timer in astable mode.
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Time High (T1) is the duration when the output is high (5V). The formula to calculate it is:
T1 = 0.693 × (R1 + R2) × C1
Substituting the values:
T1 = 0.693 × (1000 + 100000) × 0.00001 = 0.699 seconds
So, T1 = 699 milliseconds.
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Time Low (T2) is the duration when the output is low (0V). It can be calculated with the formula:
T2 = 0.693 × R2 × C1
Substituting the values:
T2 = 0.693 × 100000 × 0.00001 = 0.693 seconds
So, T2 = 693 milliseconds.
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Time Period (T) is the total time of one complete cycle (high + low). It is the sum of T1 and T2, or it can be calculated using:
T = 0.693 × (R1 + 2 × R2) × C1 or T = T1 + T2
Substituting the values:
T = 0.693 × (1000 + 2 × 100000) × 0.00001 = 1.393 seconds
So, T = 1.393 seconds.
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Frequency (F) is the reciprocal of the time period:
F = 1.44 / (R1 + 2 × R2) × C1 or F = 1 / T
Substituting the values:
F = 1.44 / (1000 + 2 × 100000) × 0.00001 = 0.718 Hertz
So, F = 0.718 Hz.
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Duty Cycle is the percentage of time the output is high during the period. It can be calculated as:
Duty Cycle = (T1 / T) × 100
Substituting the values:
Duty Cycle = (0.699 / 1.393) × 100 = 50.249%
So, Duty Cycle = 50.249%.
This is how you can calculate the time high, time low, period, frequency, and duty cycle for a 555 timer in astable mode based on given resistor and capacitor values. Using a 555 timer calculator can simplify these calculations when designing circuits for projects.