Adafruit
Adafruit PCT2075 Temperature Sensor - STEMMA QT / Qwiic
The Adafruit PCT2075 Temperature Sensor is a precise, affordable I2C temperature sensor and a drop-in replacement for the classic LM75. With an 11-bit ADC (c...
The Adafruit PCT2075 Temperature Sensor is a precise, affordable I2C temperature sensor and a drop-in replacement for the classic LM75. With an 11-bit ADC (compared to the LM75's 9-bit), it delivers finer temperature resolution. Three-state address pins allow up to 27 sensors on a single I2C bus — over three times the LM75's limit of 8.
The PCT2075 measures ambient temperature and includes a configurable high-temperature threshold alert. When the current reading exceeds the set threshold, an interrupt output is raised. Additional registers let you adjust alerting behaviour and measurement timing. STEMMA QT connectors make wiring solderless and simple.
Key Features
- 11-bit Temperature ADC – Higher resolution than the 9-bit LM75 it replaces
- I2C Interface – Code-compatible with LM75; drop-in upgrade
- Up to 27 Sensors per Bus – Three-state address pins (high, low, floating)
- Over-Temperature Alert – Configurable threshold with interrupt output
- STEMMA QT / Qwiic – Solderless STEMMA QT connectors for easy daisy-chaining
- Breadboard Friendly – Standard 0.1″ header pinout
Ideal For
- Ambient temperature monitoring in electronics projects
- Upgrading existing LM75-based designs with better resolution
- Multi-sensor temperature arrays (up to 27 on one bus)
- Over-temperature alert and shutdown systems
Resources
- PCT2075 Learn Guide (schematics, pinouts, libraries, datasheets)
Jargon buster
Plain-language definitions for the technical terms used above.
- ADC
- An analogue-to-digital converter reads a changing voltage and turns it into a number the microcontroller can use. It matters when connecting analogue sensors such as light, sound, or variable-resistor sensors.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- STEMMA
- A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.
- STEMMA QT
- A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.
Find this product in
Brands
Related Tutorials
Free guides on learn.littlebird.com.au
