Measure Rectified 50Hz Voltage Using Analog Input
Posted: 31 Jan 2020, 02:08
I am trying to measure the high current going to a bidirectional an electrolysis cell. The power source is from a transformer with about 9V AC at 50Hz. This goes through a full bridge rectifier. The current should be between 10 and 20 Amps.
At the moment I am using a FET current sensor that outputs a voltage between 0V and 5V, with 2.5V corresponding to zero current. I have put this through a voltage divider and connected it to the analog input of an ESP8266.
The problem is the current varies like a rectified sinewave and the current reading depends on where in the cycle the reading was taken. This means anything between 0A and 20Amps. Now I don't need an RMS reading, just an approximation of this. I have tried using the oversampling feature in ESPEasy, but this doesn't resolve the problem.
Another possibility would be to use a capacitor on the analog input to the ESP8266, thus smoothing out the value. I am not sure if this might distort the result because the values are using this offset values, that is zero current is equal to 2.5V. If this is the best option, what size capacitor should I use?
Any assistance would be appreciated.
At the moment I am using a FET current sensor that outputs a voltage between 0V and 5V, with 2.5V corresponding to zero current. I have put this through a voltage divider and connected it to the analog input of an ESP8266.
The problem is the current varies like a rectified sinewave and the current reading depends on where in the cycle the reading was taken. This means anything between 0A and 20Amps. Now I don't need an RMS reading, just an approximation of this. I have tried using the oversampling feature in ESPEasy, but this doesn't resolve the problem.
Another possibility would be to use a capacitor on the analog input to the ESP8266, thus smoothing out the value. I am not sure if this might distort the result because the values are using this offset values, that is zero current is equal to 2.5V. If this is the best option, what size capacitor should I use?
Any assistance would be appreciated.