Voltage Divider (with optional load)

Ideal: Vout = Vin · R2 / (R1 + R2)

With load: R2′ = (R2 || RL), then Vout = Vin · R2′ / (R1 + R2′)

Solves (ideal):

• R1 = R2 · (Vin/Vout − 1)
• R2 = R1 · Vout/(Vin − Vout)
• Vin = Vout · (R1 + R2)/R2

With load, first solve R2′ = Vout·R1/(Vin − Vout), then recover R2 = (R2′ · RL)/(RL − R2′) or RL = (R2′ · R2)/(R2 − R2′).