Liquid discharge apparatus and head unit

A liquid discharge apparatus comprising:

• a transport section configured to transport a medium;
• a discharge section configured to discharge liquid by supply of a drive signal;
• a detection circuit configured to detect residual vibration generated in the discharge section;
• a determination circuit configured to determine whether or not the discharge section is normal in accordance with the residual vibration;
• a first transmission gate to which a first voltage signal held at a first voltage is supplied and configured to selectively couple the discharge section and the detection circuit;
• a first signal output circuit to which a second voltage is input and configured to output a first signal held at the first voltage by switching on and off of a first switching element;
• and
• a second signal output circuit to which the second voltage is input and configured to output a second signal held at the first voltage by switching on and off of a second switching element at a timing different from a timing at which the first switching element is switched on and off, wherein
• the first voltage signal is a signal obtained by synthesizing at least the first signal and the second signal.