Relative Humidity Sensor User Manual

Order Code: RH-BTA

The Relative Humidity Sensor can be used to measure relative humidity in the air as part of a weather station, or to do any of the following:

  • Monitor indoor humidity
  • Optimize conditions in a greenhouse or terrarium
  • Determine when static electrical discharges will be a problem
  • Study transpiration rates of plants by monitoring relative humidity in sealed jars containing plants

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.

Compatible Software

Choose a platform below to see its compatibility requirements.

LabQuest 2

Full Support

The Relative Humidity Sensor is fully supported with LabQuest 2 (version 2.8.5), a standalone data logger with built-in graphing and analysis software.

Learn more about LabQuest 2 »

InterfaceGraphical Analysis 4 for Computers
Version 4.10
Logger Pro
Version 3.15
Logger Lite
Version 1.9.4
LabQuest MiniFull supportFull supportFull support
LabQuest 2Full supportFull supportFull support
LabQuest StreamFull support 1Full supportFull support 2
Go!LinkFull supportFull supportFull support

Compatibility Notes

  1. Connect LabQuest Stream via USB. Future software updates will support connection via Bluetooth® technology
  2. Connect LabQuest Stream via USB. Wireless connection is not supported.
InterfaceGraphical Analysis 4 for Chrome
Version 4.10
LabQuest MiniFull support
LabQuest 2Full support
LabQuest StreamFull support 1
Go!LinkFull support

Compatibility Notes

  1. Connect LabQuest Stream via USB. Future software updates will support connection via Bluetooth® technology
InterfaceGraphical Analysis 4 for iOS
Version 4.10
Graphical Analysis GW for iOS
Version 4.0.6
LabQuest StreamFull supportFull support
LabQuest 2Full support 1Full support 1

Compatibility Notes

  1. iOS and Android devices can only connect to LabQuest 2 via Wireless Data Sharing.
InterfaceGraphical Analysis 4 for Android
Version 4.10
Graphical Analysis GW for Android
Version 3.2
Google Science Journal
Version 1.2.259
LabQuest StreamFull supportFull supportIncompatible
LabQuest 2Full support 1Full support 1Incompatible

Compatibility Notes

  1. iOS and Android devices can only connect to LabQuest 2 via Wireless Data Sharing.

Getting Started

  1. Connect the sensor to the interface (LabQuest Mini, LabQuest 2, etc.).
  2. Start the appropriate data-collection software (Logger Pro, Logger Lite, LabQuest App) if not already running, and choose New from File menu. The software will identify the sensor and load a default data-collection setup. You are now ready to collect data.

If you are collecting data using a Chromebook™, mobile device such as iPad® or Android™ tablet, or a Vernier wireless sensor or interface, please see the following link for up-to-date connection information:

Using the Product

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


Optional Calibration Procedure

You should not have to perform a new calibration when using the Relative Humidity Sensor. A calibration equation is stored on each Relative Humdity Sensor before they are shipped, which is used as default by Vernier software. If you would like to calibrate the Relative Humidity Sensor, you can find instructions at



0% to 95%


200 μA @ 5 VDC

Response Time
(time for a 90% change in reading)

  • In still air: 60 minutes (typical)
  • With vigorous air movement: 40 seconds (typical)


0.04% RH

Stored calibration

  • slope: 30.43%/V
  • intercept: –25.81%

Accuracy as shipped

±10% RH

Operating Temperature Range

0 to 85°C

Care and Maintenance

Do not wrap the cable tightly around the sensor for storage. Repeatedly doing so can irreparably damage the wires and is not covered under warranty.

The Relative Humidity Sensor should not be used in a condensing environment. Condensation can damage the probe and is not covered under warranty.

How the Sensor Works

This sensor uses a capacitive polymer to sense humidity. An integrated circuit then produces an output voltage which varies with relative humidity. The response time of the unit in moving air is much shorter than in still air. In some cases, you may want to create air currents (by moving the sensor or using a fan) to speed up the response of the sensor.

The sensor is slightly light sensitive. The housing is designed to minimize the amount of light that can penetrate the sensor opening. The sensor output is somewhat affected by temperature. This effect is negligible at low relative humidity readings, but increases at high humidities. If you want to correct for this error, you can create different calibration files for different temperatures. In most cases, this is unnecessary.


For troubleshooting and FAQs, see

Repair Information

If you have watched the related product video(s), followed the troubleshooting steps, and are still having trouble with your Relative Humidity Sensor, 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.


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.

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.