# How to use a multimeter?

## Check the circuits (continuity test)

> **Warning** The tested object should be disconnected from the power supply (de-energized)!

Using a multimeter, check the absence of a short circuit (check the loop):

* Set the multimeter to the loop check mode.
* Test the multimeter by shorting the probes. A unit that operated properly makes a distinctive sound.
* The red probe is connected to the “+ ”pin, the black probe — to the “-” / ”GND” pin. If the circuit is short, a sound is heard.

![Loop check mode](../../assets/startPDBtest.jpg)

1\. Check OPEN CONDITION of the following circuits (absence of the multimeter sound signal):

* “BAT+” and “BAT-”
* “12V” and “GND”
* “5V” and “GND”

2\. Check CLOSED CONDITION of the following circuits (presence of the multimeter sound signal):

* “BAT-” with every contact marked “-” and “GND”
* “BAT+”, with every contact marked “+”

## Checking for voltage

Using a multimeter, you need to make sure that the voltage converters located on the power distribution board are working properly and provide the voltage of 5V and 12V, respectively.

* Switch the multimeter to the "Measuring DC voltage" mode
* Select the upper limit of the measured voltage (in our case, not more than 20)
* Make sure the battery is connected
* Make the following measurements:
   1. Measure the battery voltage (between BAT+ and BAT-). It should be between 14.0 V to 16.8 V
   2. Measure the voltage at the 5V output. It should not exceed 5.5 V
   3. Measure the voltage at the 12 V output. It should not exceed 12.5 V

After measurement:

* disconnect the battery
* turn off the multimeter