# Analog input

An analog input pin can read a voltage level that ranges from the supply voltage of your board 3.3 v (**3.3V**) down to 0 v (**GND**). The value returned to your program from reading the pin is not the actual voltage value but a binary digital number that represents the input signal level.

![Pins on edge of board](/static/cp/learn/pins-tutorial/analog-input/analog-input-header.jpg)

## Experiments

There are several experiments to let you test out the concepts you learn in the analog input sections. You'll need a few things to in order to perform some of the experiments. 

* (3) [Alligator clip leads](https://www.adafruit.com/product/1008)
* [Variable resistor](https://www.adafruit.com/product/562) - use you own [graphite resistor](/learnsystem/pins-tutorial/devices/make-a-resistor#input-resistor)

## Sections

```codecard
[{
  "name": "Analog to digital",
  "description": "Learn about converting an analog signal into digital numbers.",
  "url":"/learnsystem/pins-tutorial/analog-input/analog-to-digital",
  "imageUrl":"/static/cp/learn/pins-tutorial/analog-input/analog-digital-thumb.jpg"
}, {
  "name": "Read analog",
  "description": "Read various voltages on a pin.",
  "url":"/learnsystem/pins-tutorial/analog-input/read-analog",
  "imageUrl":"/static/cp/learn/pins-tutorial/analog-input/read-analog-thumb.jpg"
}]
```
