Neon bulb resistor calculation

R = (Vp - Vb) / Ib

• R = resistor value, in Ohms
• Vp = power supply voltage, in Volts
• Vb = neon lamp voltage, in Volts
• Ib = neon lam current, in Amperes

R = (120 - 90) / 0.0005 = 60,000 (60 kΩ)