An ECG sensor chip used in a wearable appliance includes； a switch controlled by a switching signal, an amplifier that amplifies a difference between first and second ECG signals, and a location indicator that generates the switching signal. The switch passes either a first ECG signal or second ECG signal in response to the switching signal.本發明提供一種用於可穿戴器具中的心電圖感測器晶片，所述心電圖感測器晶片包含：開關，其由開關信號控制；放大器，其放大第一心電圖信號與第二心電圖信號之間的差；以及位置指示器，其產生所述開關信號。所述開關回應於所述開關信號而傳遞第一心電圖信號或第二心電圖信號。
