本論文設計一個應用於電化學感測器電極改質之 恆電流儀，所提出之恆電 流儀可以做為感測器開發過程中，將工作電極之電極性質改變之任務，例如，將 銀電極改質成為氯化銀。 在系統設計方面，本文所提出之恆電流儀是由一個混和訊號 32位元的微控 制器積體電路 (EFM32)、四個電壓隨耦器、一個 12bit的數位類比轉換 器 (DAC)、 一個 12bit的類比數位轉換器 (ADC)、一組分壓電路、一個 TTL轉 USB模組、一 個運算放大器 (OPA)以及三組反向放大器電路組成。其中 EFM32是用來控制 DAC以及 ADC DAC是用來設定產生電極改質所需之恆電流電壓， ADC用來 接收實驗過程中產生的參考電極之反應電壓，此反應電壓將經由 EFM32連結 TTL轉 USB模組傳輸至個人電腦，實驗過程中的即時實驗結果可利用 LabVIEW觀測與分析。 在系統驗證方面，除了我們所設計之恆電流儀電路，在感測器方面採用禪譜 科技公司之 TE100電極試片以及 ASPE銀電極試片，電解液部分則是採用其中 不同濃度氯化鉀標準溶液 分別為 1M、 0.1M、 0.01M、 0.001M氯化鉀溶液 進行 電極改質，其中， TE100電極試片擔任輔助電極 (Counter)和參考電極 ( ASPE銀 電極試片則是作為工作電極。利用 2 mA之恆電流施加在感測器上，以 不同濃度之 KCL溶液，進行分析觀察參考電極之電位變化，當電位由一個電位 轉換到另一個恆電位時，代表電極之性質轉態完成，也可以透過電極的顏色同步 觀察，其電化學反應之過程。經實驗驗證，電極性質的轉換時間與電流大小以及 溶液濃度成反比，電流越大轉換時間越短，濃度越高轉換時間一樣越短。 本論文設計之恆電流儀已經驗證可以應用於電化學感測器電極改質，或是， 另一種應用方式，可以根據觀察參考電極之電位變化時間，來測試未知 KCL溶 液之濃度。

In this paper, we propose a design of a Galvanostat for modifying the electrodes of electrochemical sensors. The proposed Galvanostat can be used in the sensor development process to alter the properties of the working electrode, such as modifying a silver electrode into a silver chloride electrode. The proposed Galvanostat consists of a 32-bit mixed-signal microcontroller (EFM32), four voltage followers, a 12-bit digital-to-analog converter (DAC), a 12-bit analog-to-digital converter (ADC), a voltage divider circuit, a TTL-to-USB module, an operational amplifier (OPA), and three inverting amplifier circuits. The EFM32 microcontroller controls both the DAC and ADC. The DAC is responsible for setting the voltage required to generate the constant current for electrode modification, while the ADC receives the reaction voltage from the reference electrode during the experiment. This reaction voltage is transmitted to a personal computer via the EFM32 and TTL-to-USB module, where real-time experimental results can be monitored and analyzed using LabVIEW. To validate the system, we used the TE100 electrode strip and the ASPE silver electrode strip from Zensor R&D Co., Ltd. as sensor components. Various concentrations of potassium chloride (KCl) standard solutions (1M, 0.1M, 0.01M, and 0.001M) were used as electrolytes for electrode modification. The TE100 electrode strip served as the counter electrode and reference electrode, while the ASPE silver electrode strip was used as the working electrode. A constant current of 2 mA was applied to the sensor, and the potential variation of the reference electrode was analyzed under different KCl solution concentrations. The transition of electrode properties was considered complete when the potential shifted from one value to another steady potential. This transition could also be visually observed through the color change of the electrode, indicating the electrochemical reaction process. Experimental results demonstrated that the transition time of electrode modification is inversely proportional to both the applied current and the KCl solution concentration. Higher current and higher KCl concentration resulted in shorter transition times. The proposed Galvanostat has been successfully verified for use in electrochemical sensor electrode modification. Additionally, another potential application of this system is the determination of unknown KCl solution concentrations based on the observation of reference electrode potential transition times.