Use these websites to check C1, R1, R2 values for NE555 in astable mode:
https://ohmslawcalculator.com/555-astable-calculator
https://www.omnicalculator.com/physics/ne555-astable
Recommended values:
C1: 1nF (1000pF) capacitor
R1: 2.2k
R2: 5.6k
This setup gives a 58.21% duty cycle at 107.66kHz. The frequency is 107.46kHz. These components are standard. For non-standard values, R1 can be 1.4943k and R2 a 6.8k precision resistor. For better accuracy, use an MCU. NE555's capacitor timing can degrade. The duty cycle shouldn't drop below 50%. Avoid using values under 1kΩ for R1 and R2.
Calculate frequency and duty cycle:
Frequency: f = 1.44 / ((R1 + 2 * R2) * C)
Duty cycle: D = T_high / T_total
T_high = ln(2) * R1 * R2 * C1
T_low = ln(2) * R2 * C1
T_total = T_high + T_low
Using the values:
C1: 1nF (1000pF or 1 * 10e-9 F) capacitor
R1: 2.2k
R2: 5.6k
f = 1.44 / ((2200 + 2 * 5600) * 1 * 10e-9) = 10746.268656716416
D calculations:
ln(2) = 0.693
C1 = 10e-9
T_high = 0.693 * (2200 + 5600) * 10e-9 = 5.4053999999999994e-05
T_low = 0.693 * 5600 * 10e-9 = 3.8808e-05
T_total = 9.286199999999999e-05
D = 0.582089552238806 or 58.208%