555

Do you mean one of these?

• Math value: 555 as a number

  • Factorization: 555 = 3 × 5 × 37
  • Divisors: 1, 3, 5, 15, 37, 111, 185, 555
  • Sum of digits: 5+5+5 = 15 (divisible by 3 and 5)
  • Roman numeral: DLV
  • Binary: 555 = 1000101011₂

• Electronics: 555 timer IC

  • Key modes: astable (oscillator) and monostable (one-shot)
  • Pinout (typical NE555): 1 GND, 2 Trigger, 3 Output, 4 Reset, 5 Control Voltage, 6 Threshold, 7 Discharge, 8 Vcc
  • Important formulas:
    • Astable f ≈ 1.44 / ((R1 + 2R2) C)
    • Astable duty cycle ≈ (R1 + R2) / (R1 + 2R2)
    • Monostable pulse width t ≈ 1.1 R C
  • Common values: supply 4.5–15 V; use a small 0.01 µF cap on control pin 5 for stability
  • Example: with R1 = 1 kΩ, R2 = 10 kΩ, C = 0.1 µF, f ≈ 685 Hz

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