# First steps Install the Joulescope User Interface (UI) on your computer, as described in [Installing the Joulescope UI](https://docs.joulescope.com/en/getting_started/install_ui.md#getting-started-install-ui). Start the Joulescope UI.  Connect the Joulescope USB port to the host computer using the provided USB cable. The UI automatically detects the connected Joulescope and starts displaying statistics data.  The Joulescope JS320 front panel has the **Voltage** and **Current** binding posts. The JS220 and JS220+ have the same connections.  To measure the current and charge, connect the Joulescope **Current** port inline between the positive output from your power source and your target device under test. The maximum voltage between any port **Current +**, **Current -**, **Voltage +**, and **Voltage -** should never exceed ±15V. All sensor ports are electrically isolated from USB, but the voltage between any port and USB ground should never exceed ±48V. To also measure voltage, power, and energy, connect the Joulescope **Voltage** ports across your power source’s positive and negative connections. Alternatively, you can connect the **Voltage** port across your target device’s positive and negative connections.  The Joulescope can be used in a variety of measurement configurations. For more common connection scenarios, see [How to Connect Your Joulescope](https://docs.joulescope.com/en/products/js320/guide/connect.md#js320-how-to-connect-your-joulescope). Operate your device under test. The **Multimeter** view shows current, voltage, power, charge, and energy. When you want to see waveforms over time, use the **Oscilloscope** view. Select **View** → **Oscilloscope**.  Have questions about a feature? In many cases, you can hover the mouse over an area of interest to see a **Tooltip**. Right-click (control-click on macOS) often brings up a context-sensitive menu. For more information on the Joulescope UI, see the [Joulescope UI User’s Guide](https://docs.joulescope.com/en/software/joulescope_ui/index.md). ## Joulescope JS110 The previous-generation Joulescope JS110 has different connections: **IN** and **OUT** ports rather than **Voltage** and **Current**. See the [JS110 Quick start](https://docs.joulescope.com/en/products/js110/guide/quick_start.md#js110-quick-start).