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Pin Connections All unused CMOS inputs must be connected to one of the rails to prevent oscillations. They must be the same voltage as the plus or ground pins for the chip. High speed CMOS (such as 74HC14) will substitute for regular, but the voltage range reduces to 2-6 volts, and it requires more input current limiting the size of input or feedback resistors. The usual voltage range for CMOS is 3-15V. Generally, 74Cxx will drive a heavier load than 40xx. Op amp balance pins (1, 5 or 8) are not used in these circuits and can be left unconnected. Op amps - LF351, LF441 or TL061: (TL types are not as good of quality.)1 pin - balance, not connected 2 pin - inverting input 3 pin - noninverting input 4 pin - minus V 5 pin - balance, not connected 6 pin - output 7 pin - plus V 8 pin - not connected Dual op amps - LF353, LF442: 1 pin - output for 2 and 3 pins 2 pin - inverting input 3 pin - noninverting input 4 pin - minus V 5 pin - noninverting input 6 pin - inverting input 7 pin - output for 5 and 6 pins 8 pin - plus V Usual small signal transistors (PN2222A) and darlington MPSA13: left = emitter center = base right = collector when looking at flat surface in front. There are six Schmidt triggers on a single chip, 74C14 or 40106: 1 pin in - 2 pin out 3 pin in - 4 pin out 5 pin in - 6 pin out 7 pin - ground 9 pin in - 8 pin out 11 pin in - 10 pin out 13 pin in - 12 pin out 14 pin - plus voltage 4020 - 14 Stage Binary Counter (divide input frequency by quantity shown): 1 - output, q12, 4096 2 - output, q13, 8192 3 - output, q14, 16,384 4 - output, q6, 64 5 - output, q5, 32 6 - output, q7, 128 7 - output, q4, 16 8 - ground 9 - output, q1, 2 10 - clock in, negative edge 11 - high reset, low run 12 - output, q9, 512 13 - output, q8, 256 14 - output, q10, 1024 15 - output, q11, 2048 16 - plus V 4017 - Decade Counter: 1 pin - output position 5 2 pin - output position 1 3 pin - output position 0, resets to high 4 pin - output position 2 5 pin - output position 6 6 pin - output position 7 7 pin - output position 3 8 pin - ground 9 pin - output position 8 10 pin - output position 4 11 pin - output position 9 12 pin - carry out, ignore 13 pin - high stop, low run 14 pin - clock in, plus edge 15 pin - high reset, low run 16 pin - plus V 74C74 - Dual D Flip-Flop, low resets: 1 - (1) clear, low resets q low (q-bar high), high run 2 - (1) data in 3 - (1) clock in, plus edge 4 - (1) preset, low resets q-bar low (q high), high run 5 - (1) q out 6 - (1) q-bar out 7 - ground 8 - (2) q-bar out 9 - (2) q out 10 - (2) preset, low resets q-bar low (q high), high run 11 - (2) clock in, plus edge 12 - (2) data in 13 - (2) clear, low resets q low (q-bar high), high run 14 - plus V 4013 - Dual D Flip-Flop, high resets: 1 - (1) q out 2 - (1) q-bar out 3 - (1) clock in, plus edge 4 - (1) reset, high resets q-bar high (q low), low run 5 - (1) data in 6 - (1) set, high resets q high (q-bar low), low run 7 - ground 8 - (2) set, high resets q high (q-bar low), low run 9 - (2) data in 10 - (2) reset, high resets q-bar high (q low), low run 11 - (2) clock in, plus edge 12 - (2) q-bar out 13 - (2) q out 14 - plus V 4071 - OR Gate (same pinout as 4081 AND Gate): 1,2 in - 3 out 5,6 in - 4 out 8,9 in - 10 out 12,13 in - 11 out 7 - ground 14 - plus V 80C95 - Tri-State Hex Buffers: 1 - high cuts all, ORed with 15 2 - in A 3 - out A 4 - in B 5 - out B 6 - in C 7 - out C 8 - ground 9 - out D 10 - in D 11 - out E 12 - in E 13 - out F 14 - in F 15 - high cuts all, ORed with 1 16 - positive voltage
By Gary Novak |
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