Is it possible to coonect the source of M1 to a defined path without knowing the coordinates?
\path (0,0) coordinate (IBGND);
\draw (IBGND) to [short,-] (15,0){};
\draw (0.5,0.5) to [C, l=$C_1$, name=C1, -] (0.5,1.5) %cap = 1
(0.5,0) -- (0.5,0.5) ;
\draw (1,1.5) node[pmos,anchor=drain,yscale=-1.5,xscale=1.5,rotate=270](M5){};
\draw (M5.drain) -- (0.5,1.5)
(M5.gate) to [short,-*] ++(0,-0.8) %%%% in this line I have to guess the coordinates of that point on the X axis
(M5.drain) node[above right] {$M_5$}
(M5.source) ++(0.5,0) node[nmos,anchor=gate,scale=1.5](M1){}
(M5.source) -- (M1.gate)
(M1.drain) node[below right] {$M_1$};
Thank you!