ECG Signal Amplifier Sch + PCB
Category: Example Projects
Designer: RANA MUHAMMAD ADNAN KHALIL
Notes
This circuit is designed in Altium Designer. This project is contains concept or differential and instrumentation amplifier. Biomedical signals are very sensitive and critical. We cannot afford noise or signal distortion at any cost. ECG signal is one of the most critical signal for the person heart condition. 1. ECG signal ranges from 10uV to 5mV in amplitude and 0.05Hz to 35Hz in frequency. 2. But the shape and pattern remains same for healthy heart. 3. If the shape or pattern changes then it indicates a problem. 4. So it is very important and critical to record the actual signal comming out of heart and amplify it with any noise to clarify that the heart is healthy or not. 5. To amplify biomedical signal, instrumentation amplifiers are used, because CMRR of instrumentation amplifier is very good. 6. It is recommended to operate the sensitive instrument on battery. 7. The utility power contains so many noise. 8. If instrument is operated from utility supply, too much filtration is needed to avoid any harmonics and noise. 9. A sample amplifier circuit for ECG signal is given in this project. 10. AD620 and AD548 are used. This circuit is a two stage amplifier. 11. This circuit is fully tested and ECG signal is recorded. 12. All files including PCB layout and gerbers are given. 13. Those who want to use this circuit as it is, they can use gerbers directly, while others can customize according to their needs. 14. PCB layout is based on two layers and SMD components are also used. 15. Rework area is also given in order to add some circuitry or components. 16. Download the files to perform more experiments. Applications: 1. This circuit can be used as a difference amplifier. 2. This circuit can be used as a pre-amplifier stage for EEG signal amplifier. 3. This circuit can be used to clarify the concept of instrumentation amplifier.