摘要
温度是影响pH值在线测量精度和长期稳定性的重要因素之一，因此在采集电路中设计温漂低、稳定性高的前级处理电路和高精度的A／D采集电路至关重要。文中采用ADI公司最新生产的低偏置电流、低失调漂移放大器ADA4505和高精度ADC芯片AD7792，设计的pH值测量电路，分辨率高、稳定性好、结构简单、功耗低，实验结果表明，该方案能在10～60℃范围内保持较高的测量精度。
Drift with time and temperature are very important factors during pH online measurement, so in pH meter design, low drift and an accurate signal chain would be required. For the purpose, a simple solution is provid- ed with a low bias current amplifier, ADA4505, and a high accurate AD convert, AD7792. The ADA4504 is used as a buffer to achieve accurate pH measurement since pH electrodes have a very large output resistance. And the AD7792 is a 16-bit ADC, which is also responsible for temperature measurement for compensation. Experiment re- sult shows that the design can keep high precision in a wide temperature range.
出处
《电子科技》
2013年第12期93-95,共3页
Electronic Science and Technology
