define(`section',`[ I: Here
resistor(right elen_*0.75); llabel(,R/2)
T: dot
line down dimen_/2 then right_ dimen_/4
Amp: opamp(,,,body=shaded "goldenrod") with .In1 at Here
line left dimen_/4 from Amp.In2 then down dimen_/4; G: ground(,,)
resistor(from T to (Amp.Out,T)); llabel(,R)
O: dot
{ arrow up dimen_*0.5 then right dimen_/4 up dimen_/4
"`$1'" above }
line to Amp.Out
dot(at T+(dimen_/4,0)); line up dimen_*0.6
capacitor(right_ Amp.Out.x-Here.x-dimen_/4,C); llabel(,2C)
line to (Here,T); dot
]')
A: section(svg_symbol(0&`#'176;))
B: section(svg_symbol(120&`#'176;)) with .I at A.O
C: section(svg_symbol(-120&`#'176;)) with .I at B.O
move right 22pt__ from C.O
ground(at (A.I,A.G)+(dimen_/3,0),,)
P:potentiometer(down_ dimen_/2,,0.75,dimen_/2) with .End at Here
line from P.Start to (A.I,P.Start); dot
resistor(up_ dimen_*0.75 from P.T1)
line to A.T
dot(at B.Amp.Out+(dimen_/3,0)); { "svg_it(V`'svg_sub(c))" at last [].n above }
resistor(down_ dimen_*0.75)
{ dot; line right (C.T.x-Here.x)/2
reversed(`diode',up_ dimen_)
line to C.T }
resistor(down_ dimen_*0.75)
dot
line from C.O right dimen_/4 then down C.O.y-Here.y then to (A.I,Here) \
then to A.I
