Vernier Software and Technology
Vernier Software & Technology

Go Direct® Current Probe User Manual

Go Direct® Current Probe

Go Direct Current is designed for exploring the basic principles of electricity. Use Go Direct Current to measure currents in low voltage AC and DC circuits. With a range of ±1 A, this sensor is ideal for use in most “battery and bulb” circuits.

Note: Vernier products are designed for educational use. Our products are not designed nor are they recommended for any industrial, medical, or commercial process such as life support, patient diagnosis, control of a manufacturing process, or industrial testing of any kind.

What's Included

  • Go Direct Current
  • Micro USB Cable

Compatible Software

Getting Started

Please see the following link for platform-specific connection information:

Bluetooth Connection

USB Connection

  1. Install Graphical Analysis 4 on your computer, Chromebook™, or mobile device. See for software availability.
  2. Charge your sensor for at least 2 hours before first use.
  3. Turn on your sensor by pressing the power button once. The Bluetooth® LED will blink red.
  4. Launch Graphical Analysis 4.
  5. Click or tap Sensor Data Collection.
  6. Click or tap your Go Direct sensor from the list of Discovered Wireless Devices. Your sensor's ID is located near the barcode on the sensor. The Bluetooth LED will blink green when it is successfully connected.
  7. Click or tap Done to enter data-collection mode.
  1. Install Graphical Analysis 4 on your computer or Chromebook. If using LabQuest 2, make sure LabQuest App is up to date. See for software availability or to update LabQuest App.
  2. Connect the sensor to the USB port.
  3. Launch Graphical Analysis 4 or turn on LabQuest 2. You are now ready to collect data.

Charging the Sensor

Connect Go Direct Current to the included USB Charging Cable and any USB device for two hours.

You can also charge up to eight Go Direct Current Probes using our Go Direct Charge Station, sold separately (order code: GDX-CRG). An LED on each Go Direct Current indicates charging status.


Orange LED next to the battery icon is solid while the sensor is charging.

Fully charged

Green LED next to the battery icon is solid when the sensor is fully charged.

Powering the Sensor

Turning on the sensor

Press button once. Red LED indicator flashes when unit is on.

Putting the sensor in sleep mode

Press and hold button for more than three seconds to put into sleep mode. Red LED indicator stops flashing when sleeping.

Connecting the Sensor

See the following link for up-to-date connection information:

Connecting via Bluetooth

Ready to connect Red LED next to the Bluetooth icon flashes when sensor is awake and ready to connect.
Connected Green LED next to the Bluetooth icon flashes when sensor is connected via Bluetooth.

Connecting via USB

Connected and charging Orange LED next to the battery icon is solid when the sensor is connected to Graphical Analysis via USB and the unit is charging. LED next to Bluetooth icon is off.
Connected, fully charged Green LED next to the battery icon is solid when the sensor is connected to Graphical Analysis via USB and fully charged. LED next to Bluetooth icon is off.
Charging via USB,
connected via Bluetooth
Orange LED next to the battery icon is solid when the sensor is charging. Green LED next to the Bluetooth icon flashes.

Identifying the Sensor

When two or more sensors are connected, the sensors can be identified by tapping or clicking Identify in Sensor Information.

Using the Product

Connect the sensor following the steps in the Getting Started section of this user manual.

Go Direct Current was designed to be wired in series with the circuit. Currents in either direction can be measured. The current will be indicated as positive if current flows in the direction of the arrow on the box (from the red lead to the black lead).

Go Direct Current has two ranges. The ±1 A (±1000 mA) range is suitable for most circuit experiments and will likely be the range you use most often. The ±0.1 A (±100 mA) range is useful for experiments where you expect very small electric currents, such as electromagnetically-induced currents. Switch between the ranges by using the switch on the base of the sensor. Note: The range setting is not indicated in Graphical Analysis. If currents greater than 100 mA are measured on the smaller range, the data will flat-line just above 100 mA.

Calibrating the Sensor

You should not have to perform a new calibration when using Go Direct Current in the classroom. A stored calibration is set for the sensor before it is shipped.

However, you may consider “zeroing” the sensor before the start of an experiment. This is done by shorting out the leads of the sensor, then choosing the Zero option in the data-collection software. This option adjusts the calibration offset but does not adjust the calibration gain.


Current Probe range

±1 A and ±0.1 A

Maximum voltage on any input

±10 V

Maximum non-damaging current

1.5 A and 0.5 A

Input impedance (between inputs)

0.1 Ω (±1 A range) and 1 Ω (±0.1 A range)

Input impedance (to ground)

10 MΩ




0.031 mA (±1 A range) and 0.003 mA (±0.1 A range)


300 mA Li-Poly

Battery life (single full charge)

~24 hours

Battery life (long term)

~500 full charge cycles (several years depending on usage)

Care and Maintenance

Battery Information

Go Direct Current contains a small lithium-ion battery. The system is designed to consume very little power and not put heavy demands on the battery. Although the battery is warranted for one year, the expected battery life should be several years. Replacement batteries are available from Vernier (order code: GDX-BAT-300).

Storage and Maintenance

To store Go Direct Current for extended periods of time, put the device in sleep mode by holding the button down for at least three seconds. The red LED will stop flashing to show that the unit is in sleep mode. Over several months, the battery will discharge but will not be damaged. After such storage, charge the device for a few hours, and the unit will be ready to go.

Exposing the battery to temperatures over 35°C (95°F) will reduce its lifespan. If possible, store the device in an area that is not exposed to temperature extremes.

Water Resistance

Go Direct Current is not water resistant and should never be immersed in water.

If water gets into the device, immediately power the unit down (press and hold the power button for more than three seconds). Disconnect the sensor and charging cable, and remove the battery. Allow the device to dry thoroughly before attempting to use the device again. Do not attempt to dry using an external heat source.

How the Sensor Works

Go Direct Current contains a sensing element and signal conditioning amplifier. The sensing element is a 0.1 Ω (or 1 Ω , for the smaller range) resistor connected between the red and black leads. As the current passes through the resistor, a small potential difference is measured across this resistor. This potential difference is input to the signal conditioning amplifier. The final result is that a voltage is produced from the amplifier that can be measured by sensor.


If Go Direct Current is not operating as expected, connect the sensor to Graphical Analysis either via Bluetooth or USB. Connect Go Direct Current to a DC power supply in series with a known resistance. Use a voltage probe or voltmeter to measure the voltage of the supply. Compare the measured current against the current calculated from Ohm’s law. Note: We recommend a battery for this test, since some DC power supplies may not deliver clean DC voltage.

For additional troubleshooting and FAQs, see

Repair Information

If you have watched followed the troubleshooting steps and are still having trouble with your Go Direct Current, contact Vernier Technical Support at or call 888-837-6437. Support specialists will work with you to determine if the unit needs to be sent in for repair. At that time, a Return Merchandise Authorization (RMA) number will be issued and instructions will be communicated on how to return the unit for repair.


Item Order Code

Micro USB Cable


USB-C to Micro USB Cable


Go Direct 300 mAh Replacement Battery



Vernier warrants this product to be free from defects in materials and workmanship for a period of five years from the date of shipment to the customer. This warranty does not cover damage to the product caused by abuse or improper use. This warranty covers educational institutions only.


When disposing of this electronic product, do not treat it as household waste. Its disposal is subject to regulations that vary by country and region. This item should be given to an applicable collection point for the recycling of electrical and electronic equipment. By ensuring that this product is disposed of correctly, you help prevent potential negative consequences on human health or on the environment. The recycling of materials will help to conserve natural resources. For more detailed information about recycling this product, contact your local city office or your disposal service.

Battery recycling information is available at

Do not puncture or expose the battery to excessive heat or flame.

The symbol, shown here, indicates that this product must not be disposed of in a standard waste container.

Contact Support

Fill out our online support form or call us toll-free at 1-888-837-6437.

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