Hi all,
I am trying to implement a simple EMG circuit using the INA333 instrumentation amplifier (schematic shown below)
When implementing this circuit, I am getting a output with an offset of approx 4V. Could anyone please explain why I am getting this offset instead of Vs/2 (which should be approx 2.5V) ?
Below are some observations done from the actual circuit implementation and some changes from the schematic below:
1) Resistors R1 and R2 are actually 200 Kohms in the actual circuit, and resistor R3 is 150 ohms
2) VG1 and 2 are connected to the electrodes in the actual circuit and an additional reference electrode is connected directly to Vs/2 supply.
3) Although the reference electrode is connected to Vs/2 supply, I am still getting approx 1.1V as the offset voltage (baseline) at the output of the two detection electrodes. Although I am getting aprox 1.1V at both detection electrodes, if I simulate this on TINA simulator, the output baseline is still Vs/2 (as shown below)
I am trying to implement a simple EMG circuit using the INA333 instrumentation amplifier (schematic shown below)
When implementing this circuit, I am getting a output with an offset of approx 4V. Could anyone please explain why I am getting this offset instead of Vs/2 (which should be approx 2.5V) ?
Below are some observations done from the actual circuit implementation and some changes from the schematic below:
1) Resistors R1 and R2 are actually 200 Kohms in the actual circuit, and resistor R3 is 150 ohms
2) VG1 and 2 are connected to the electrodes in the actual circuit and an additional reference electrode is connected directly to Vs/2 supply.
3) Although the reference electrode is connected to Vs/2 supply, I am still getting approx 1.1V as the offset voltage (baseline) at the output of the two detection electrodes. Although I am getting aprox 1.1V at both detection electrodes, if I simulate this on TINA simulator, the output baseline is still Vs/2 (as shown below)