If you attach a higher voltage, you may permanently damage your Raspberry Pi. Important: The Raspberry Pi GPIOs support voltages only up to 3.3V. However, you can use an external analog-to-digital converter like the MCP3008 to read analog signals with the Raspberry Pi. The Raspberry Pi doesn’t have an analog-to-digital converter (ADC) interface to read analog sensors. The Raspberry Pi GPIOs provide the following peripheral interface options: 1 was the very first Raspberry Pi board released and has a slightly different pinout from all the other boards.
The following table shows the Raspberry Pi pinout, it shows all GPIOs, their corresponding physical pin numbers, their Broadcom numbering, and corresponding features. For example, GPIO 18 corresponds to pin 12. There are several ways to refer to a GPIO pin: its name (which is known as GPIO numbering or Broadcom numbering) or its corresponding pin physical number (which corresponds to the pin’s physical location on the header).
Raspberry Pi Pinout (click on the image to see full-size)