.PS
# Schottky.m4
# 4-input positive NAND: the Schottky option for transistors (TI TTL data book)
 cct_init

 tic = dimen_/4
 rlen = dimen_*3/4

E1: dot; line up_ tic
Q1: bi_trans(,,dEBCBUS) with .E at Here; line left tic from Q1.B; B1: Here
 resistor(up_ rlen from Q1.C); llabel(,\SI{3}{\kilo{}})
B2: dot; line right_ tic
Q2: bi_trans(up_ dimen_,,dEBCBUS) with .B at Here
 line from Q2.E to (Q2.E,E1); dot
Gnd: "GND" ljust at Here+(dimen_/2,0)
 dot(at Q2.C)
 { line to (Gnd,Here); "Y" ljust } 
 line to (Q1.C,Here); dot
 resistor(up_ rlen); llabel(,\SI{4}{\kilo{}}); B4: dot; line right_ tic; up_
Q4: bi_tr with .B at Here
 line from Q4.E to Q2.C
 line up_ tic from B4
Q5: bi_trans(,,dEBCBUS) with .E at Here; line left_ tic from Q5.B; B5: dot
 line from Q5.C to (Q4.C,Q5.C); dot
 { line to Q4.C }
 resistor(up_ rlen); llabel(,iflatex(120,"120")); dot
Vcc: "Vcc" ljust at (Gnd,Here)
 dot(at (B5,Vcc))
 resistor(to (Here,Q5.C)); llabel(,\SI{8}{\kilo{}})
 diode(from (B4,Q2.C) to (B5,Q2.C),Z)
 line to (Here,Q5.C)
 diode(from B4 to (Here,B4),Z); dot
 line left_ tic; up_
Q3: bi_trans(,,dEBCBUS) with .C at Here; line left_ tic from Q3.B; B3: Here
 line from Q3.E to (Q3.E,B2); dot
 dot(at (B1,Here)); resistor(down_ to (Here,Q1.C)); rlabel(,\SI{1.5}{\kilo{}}); line to B1
 resistor(down_ from B3 to (B3,B2)); rlabel(,\SI{12}{\kilo{}}); line to B2
 line from Vcc to (B3,Vcc); resistor(down_ to (Here,Q5.C))
 rlabel(,\SI{20}{\kilo{}})
 line to B3
 ground(at (Q3.C,Gnd),,F); dot

 for i=0 to 3 do {
   dot(at (B3+(0,tic*i)))
   line left_ tic*i; diode(left_ dimen_,Z); dot
   {line down_ dimen_; reversed(`diode',down_ dimen_,Z); line to (Here,Gnd)
    if i==3 then { line to Gnd } else { dot }}
   line left_ tic*(4-i); ifpostscript(,`sprintf("\char%g",64+(4-i)) rjust')
   }

.PE