I take piezo that arduino ultrasonic board has.
This piezo is similar with so I replace it capacitor in circuit diagram.
And want to make energy transfer and data transfer device.
(I'm sorry I don't know how to rotate picture)
The problem is
It is working well at not amplifier circuit like upper diagram.
I check it with oscilloscope and it working well with 200mV peak.
But I want to make circuit 36V not a 5V that inital arduino voltage.
So I make N-mosfet amplifier but it seems that not working.
I think the -(minus) voltage is a reason that made by capacitor.
Does there any way to solve my problem??