74-series chip pinouts and truth tables

Gates

• 74LS00Quad 2-input NAND gateIn the Breadboard Simulator
• 74LS02Quad 2-input NOR gateIn the Breadboard Simulator
• 74LS04Hex inverterIn the Breadboard Simulator
• 7406Hex inverter, open collector, 40 mAIn the Breadboard Simulator
• 7407Hex buffer, open collector, 40 mAIn the Breadboard Simulator
• 74LS08Quad 2-input AND gateIn the Breadboard Simulator
• 74LS10Triple 3-input NAND gateIn the Breadboard Simulator
• 74LS11Triple 3-input AND gateIn the Breadboard Simulator
• 74LS14Hex Schmitt-trigger inverter
• 74LS20Dual 4-input NAND gateIn the Breadboard Simulator
• 74LS21Dual 4-input AND gateIn the Breadboard Simulator
• 74LS27Triple 3-input NOR gateIn the Breadboard Simulator
• 74LS308-input NAND gateIn the Breadboard Simulator
• 74LS32Quad 2-input OR gateIn the Breadboard Simulator
• 74LS86Quad 2-input XOR gateIn the Breadboard Simulator
• 74LS125Quad buffer, three-stateIn the Breadboard Simulator
• 74HCT4075Triple 3-input OR (CMOS, TTL inputs) gateIn the Breadboard Simulator

Decoders

• 74LS42BCD to decimal, 1-of-10, active-lowIn the Breadboard Simulator
• 74LS47BCD to 7-segment, active-low, open collectorIn the Breadboard Simulator
• 74LS48BCD to 7-segment, active-high, 2 kΩ pull-upsIn the Breadboard Simulator
• 74LS1383-to-8 line decoder, active-lowIn the Breadboard Simulator
• 74LS139Dual 2-to-4 line decoder, active-lowIn the Breadboard Simulator

Encoders

• 74LS14710-to-4 line priority encoder (decimal to BCD)
• 74LS1488-to-3 line priority encoder

Multiplexers

• 74LS1518-to-1 multiplexerIn the Breadboard Simulator
• 74LS153Dual 4-to-1 multiplexerIn the Breadboard Simulator
• 74LS157Quad 2-to-1 multiplexerIn the Breadboard Simulator

Arithmetic

• 74LS834-bit binary full adder (original pinout)In the Breadboard Simulator
• 74LS854-bit magnitude comparatorIn the Breadboard Simulator
• 74LS2834-bit binary full adderIn the Breadboard Simulator

Flip-flops

• 74LS74Dual D-type flip-flop with preset and clear
• 74LS76Dual JK flip-flop with preset and clear
• 74LS112Dual JK flip-flop, negative-edge triggered
• 74LS175Quad D-type flip-flop with clear

Latches and registers

• 74LS373Octal transparent latch, three-state
• 74LS374Octal D-type flip-flop, three-state

Counters

• 74LS90Decade counter
• 74LS934-bit binary counter
• 74LS161Synchronous 4-bit binary counter, asynchronous clear
• 74LS163Synchronous 4-bit binary counter, synchronous clear
• 74LS192Synchronous up/down decade counter
• 74LS193Synchronous up/down 4-bit binary counter

Shift registers

• 74LS1648-bit serial-in, parallel-out shift register
• 74LS1658-bit parallel-in, serial-out shift register
• 74LS1944-bit bidirectional universal shift register

Buffers

• 74LS126Quad buffer, three-state, active-high enable
• 74LS244Octal buffer / line driver, three-stateIn the Breadboard Simulator
• 74LS245Octal bus transceiver, three-state

Reading a 74-series part number

The number after 74 names the function: every 7400 is a quad 2-input NAND and every 74138 is a 3-to-8 decoder, whoever makes it. The letters in the middle name the technology. LS is low-power Schottky TTL, the family most teaching labs stock; HC and HCT are CMOS parts that use far less power. Parts with the same number generally share a pinout across families, though their voltages and currents differ.

Every chip here runs from a single 5 V supply. Most put VCC on the last pin and GND on the pin diagonally opposite — pin 14 and pin 7 on a 14-pin package, pin 16 and pin 8 on a 16-pin one — but a few older parts, such as the 74LS76, 74LS90 and 74LS83, put them in the middle. Each page's pin diagram shows where.