One of the pleasures of learning classic logic is that many useful functions
are available as inexpensive catalog parts. Exact suffixes vary—74LS, 74HC,
74HCT, 74LVC, CD4000, and so on—so the family and datasheet matter as much as
the middle number.
Basic gates
Classic function number
Function
7400
Four 2-input NAND gates.
7402
Four 2-input NOR gates.
7404
Six inverters.
7408
Four 2-input AND gates.
7432
Four 2-input OR gates.
7486
Four 2-input XOR gates.
7414
Six Schmitt-trigger inverters.
Flip-flops and latches
7474
Dual D-type flip-flop.
7476
Dual JK flip-flop family.
373 / 573
Octal transparent latch families.
374 / 574
Octal D-type flip-flop families.
Buffers and bus devices
244
Octal buffer / line driver.
245
Octal bidirectional bus transceiver.
125 / 126
Four three-state buffers.
Decoders and multiplexers
138
3-to-8 decoder / demultiplexer.
139
Dual 2-to-4 decoder.
151
8-input multiplexer.
153
Dual 4-input multiplexer.
157
Four 2-input multiplexers.
Counters and shift registers
161 / 163
Synchronous 4-bit counters.
164
Serial-in, parallel-out shift register.
165
Parallel-in, serial-out shift register.
595
Serial-in shift register with output latch; extremely popular for output expansion.
Useful 4000-series CMOS
CD4011
Four 2-input NAND gates.
CD4013
Dual D-type flip-flop.
CD4017
Decade counter with ten decoded outputs.
CD4040
12-stage binary ripple counter.
CD4060
Oscillator plus binary divider.
CD4066
Four bilateral analog switches; a mixed analog/digital building block.
CD4093
Four 2-input Schmitt-trigger NAND gates.
CD4511
BCD-to-seven-segment latch/decoder/driver.
The familiar numeric function is not a complete part number. For example,
74LS00, 74HC00, and 74LVC00 all perform NAND logic but have very different
electrical characteristics.
Why keep these parts around?
A single logic IC can solve a problem with no software, no boot time, no firmware
maintenance, and very predictable timing. They remain excellent parts for
interlocks, glue logic, level control, counters, pulse conditioning, and
educational circuits.