Voltage Divider

The following image of the circuit shows a voltage divider (R_SEN and R₃) that converts the sensor resistance to a voltage. The MCP6XXX op-amp acts as a voltage follower (buffer). If the op amp and resistors are ideal then V_OUT = (VDD) R₃/(R_SEN + R₃).

Advantages:

• Simplicity
• Ratiometric output (with Analog-to-Digital Converter (ADC) using V_DD as its reference voltage)
• Detection of open sensor due to failure

Disadvantages:

• Poor common mode noise rejection
• Voltage is non-linear with resistance

Sensor Examples:

• Thermistor
• Resistive Temperature Detector (RTD)
• Magneto-resistive compass

​Learn More

• Sensor Overview
• Microchip op amp product page
• Analog Temperature Sensor