# 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.