Voltage Division
Quick Reference
Voltage Division Calculations
Solved for Vout
Vout = Vs * (R2 / R1 + R2)
Solved for Bottom-half of Divider (R2)
R2 = (R1 * Vout) / (Vs - Vout)
Current at Vout
I = V / R1
Where R1 is the top-half of the divider.
Netduino Characteristics
Analog-to-Digital Convert (ADC) Impedance
The Netduino ADC has an impedance value of approximately 11kΩ.
5V to 3.3 Voltage Divider Resistor Values
When level-shifting to a 5V voltage domain to a 3.3V voltage domain for use with the Netduino ADC, the following resistor values are recommended:
R1 = 1kΩ
R2 = 2.2kΩ
More Info
Voltage division is a complex topic, and covered much more in-depth in part 5 of the electronics tutorial.