Electronics
555 Timer Calculator
Calculate resistor and capacitor values for 555 timer circuits
555 Timer Calculator
Mode
Frequency
0.48 Hz
Duty Cycle
66.7%
High Time
1.39 s
Low Time
693.00 ms
Period
2.08 s
Formulas (Astable)
f = 1.44 / ((R1 + 2×R2) × C)
Duty Cycle = (R1 + R2) / (R1 + 2×R2) × 100%
T_high = 0.693 × (R1 + R2) × C
T_low = 0.693 × R2 × C
About 555 Timer
• Astable: Continuous oscillator (LED blinking, clock signal)
• Monostable: One-shot pulse (timer, debounce)
• R1, R2: Recommended range 1kΩ - 1MΩ
💡 Tip: For 50% duty cycle, use R1 = 0.1×R2
#electronics#555#timer#oscillator