I have drawn the above circuit in LTspice. I have attached the LTspice file and the voltage waveform across R2. The waveform has sharp edges when I would expect a rounded waveform. Can anyone explain where the edges come form, please?

 

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I have drawn the above circuit in LTspice. I have attached the LTspice file and the voltage waveform across R2. The waveform has sharp edges when I would expect a rounded waveform. Can anyone explain where the edges come form, please?

At first glance I'd say it looks like rectification.

 

Why didn't you draw the full bridge rectifier in a traditional way? And you have the edges when D3 start conducting current and D4 stops conducting (jump to "0V" ), and when D4 stops and D3 starts, the voltage jumps to around 330V * 480k/(1.6G + 480k) = 100mV

 

This is the waveform at the top of C1.

 

This is the waveform at the top of C1.

But the voltage drop across R1 + R2 follows the capacitor current.

And because in your circuit capacitor is very small, we can ignore the resistors and the diode.
And if we connect a capacitor directly to a Half-wave rectified voltage, and you plot the current, you will see this shape:



And here you have an example of how you should have drawn this circuit :



In LTspice, use Ctrl+R to rotate the part and Ctrl+E to mirror the part.

 

What is the purpose of that odd circuit?

 

It is my representation of the touch switch input. C1 represents the capacitance from my finger to the touch pad. The rest is the circuit to be part of a remote light switch. Does that make sense to you?