The BP01 pressure sensor is specifically designed for blood pressure monitoring and is widely used in portable electronic sphygmomanometers. It is constructed using a precision thick-film ceramic chip enclosed in a nylon plastic package, offering high linearity, low noise, and minimal external stress. The sensor incorporates internal calibration and temperature compensation to enhance measurement accuracy, stability, and repeatability across the full scale. Within its operational range, the sensor provides an accuracy of ±1% with a zero offset not exceeding ±300μV. Other Sensors,Coolant Temperature Sensor,Level Miniature Pressure Sensor,Water Pressure Sensor Xiaogan Yueneng Electronic Technology Co., Ltd. , https://www.xgsensor.com
Working Principle: The circuit diagram of a portable electronic sphygmomanometer utilizing the BP01 is illustrated. The system consists of a bias power supply circuit (A1, A2), a pre-processing circuit (A3–A6), a display circuit (A7), and the BP01 pressure sensor itself. The device measures blood pressure within a range of 0 to 200 mmHg, with a resolution of 0.1 mmHg. It operates on a 9V laminated battery. Below is a detailed explanation of each main circuit’s function: 
Bias Power Supply Circuit: This circuit uses a dual op-amp LM10 with an integrated reference voltage. A1 functions as a non-inverting amplifier, while A2 acts as a voltage follower. Together, they amplify the internal reference voltage to serve as the bias voltage for the BP01 sensor. The formula for determining Vs is: Vs = Vref × (1 + R2/R3). With Vref set at 200 mV, and values of R2 and R3 chosen accordingly, the resulting bias voltage is 5V.
Pre-Processing Circuit: Comprising four operational amplifiers (A3–A6), this stage includes an offset compensation circuit (A3), a buffer (A5), and an amplifier (A4 and A6). The gain AV is calculated as AV = 1 + (R1/RT). Assuming no offset, the output voltage from the pre-processing stage is given by: Vout = 2 × (1 + R1/RT) × VIN, where VIN is the output from the BP01 sensor.
Display Circuit: The display is driven by three-and-a-half digit display drivers. After the BP01 signal is amplified by the pre-processing circuit, it is processed by the display driver and shown on the LCD screen.
Calibration Method: Zero-Voltage Adjustment: To adjust the zero-voltage output, the offset potentiometer RP1 is fine-tuned until the sphygmomanometer displays 000.0. At this point, the zero-pressure adjustment is complete, ensuring accurate readings under normal conditions.
August 01, 2025