Help!! I was trying to build an AC to DC power supply circuit without using transformers. I followed the circuit diagrams given online, which has the 240VAC connected to a resistor at the live and a full wave rectifier whose output was connected to a capacitor and a zener diode. The figure is given in the attachment, everything i use is the same except that the resistor R1 is connected to the live and the value is 2.2k. The output waveform i got was a square wave, not a DC straight line as expected (or close to a straight line). I'm wondering how to eliminate the square wave or how to smooth the square into a close-to-straight line. Thank you..