Hello everyone, a while ago I used the AMC1200SDUBR for a design to measure AC voltage applied to a single-phase motor with a capacitor. This is the circuit I'm using to measure the voltage:
However, I have a major issue, and it seems like the measurements I'm taking make no sense. When I turn on the equipment, it reads 100 volts, but when I turn it off and then back on after a couple of minutes for the same AC voltage, it reads 90, and then 103. It really doesn't make any sense. Did I design the circuit incorrectly? I reviewed an application note that was recommended to me, but I decided to use the circuit I showed you for my tests. What could be happening?
Note: I use a phase control, digital dimmer, to regulate the firing angle of a triac and thus control the voltage supplied to the motor.
VDD = 3.3V and 5V_ANALOG = 5.0V.
I'm using a B0505S to provide 5V_ANALOG to the chip.