Differential proportional operation circuit (addition and subtraction operation circuit) The differential proportional operation circuit is a special example of the addition and subtraction operation circuit, and the circuit structure is as shown in FIG. 5. The corresponding formula between input and output voltage is: Differential proportional operation circuit Smart Watches,Smart Bracelet,Blood Pressure Smart Watch,Health Monitor Smart Watches; C&Q Technology (Guangzhou) Co.,Ltd. , https://www.gzcqteq.com