I have implemented a "Capacitive transformerless power supply" to control a microcontroller-based circuit that contains capacitive touch sensors, and I had an "AC polarity problem"
Surprisingly, the circuit behavior became affected by the polarity of the input AC (Line & Neutral), such that:
- When the "Line" of the AC is connected to the 820nF capacitor and the "Neutral" is connected to the 100 ohm resistor –> behavior of the capacitive touch differs from connecting them in vice versa.
I have no idea how could the AC polarity affects the behavior of the supplied circuit?
Is there any reasonable explanation?
This is the schematic of the Capacitive power supply circuit I implemented:
Note that, the ground symbol in the circuit indicates the common point in the DC part, the AC source is only 2 pins (Line & Neutral)
Thanks in advance.