Components, Logic ICs

The following integrated circuits provide a range of logic functions and are pin-out compatible with the original 74 series TTL circuits dating back to the 1960s. They are all dual-in-line packages with 2.54mm (0.1″) pin spacing, making them easy to solder.

74HCT02

Quad 2-input NOR gate
eg. CD74HCT02E, SN74HCT02N

74HCT04

Hex inverter
eg. SN74HCT04N

74HCT08

Quad 2-input AND gate
eg. SN74HCT08N

74HCT14

Hex inverter, schmitt trigger
eg. SN74HCT14N

74HCT32

Quad 2-input OR gate
eg. CD74HCT32E, SN74HCT32N

74HCT74

Dual D type flip flop
eg. CD74HCT74E, SN74HCT74N

74HCT125

Quad tri–state buffer
eg. CD74HCT125E, SN74HCT125N

74HCT138

3-to-8 line decoder
eg. CD74HCT138E, SN74HCT138N

74AHCT139

Dual 2-input decoder
eg. SN74AHCT139N

74HCT157

Quad 2-to-1 selector/multiplexer
eg. SN74HCT157N, SN74HCT157NE4

74HCT245

Octal tri-state bus transceiver
eg. SN74HCT245N, SN74HCT245NE4

74HCT259

Quad 2-to-1 selector/multiplexer
eg. SN74HCT157N, SN74HCT157NE4

74HCT273

8-bit register with clear
eg. SN74HCT273N

74HCT393

Dual 4-bit counter
eg. CD74HCT393E, SN74HCT393N

74HCT688

8-bit register with clear
eg. CD74HCT688E

74HCT4075

Triple 3-input OR gate
eg. CD74HCT4075E

Homebrew 8-bit retro computing