Logic Chips and the 74 Series Families Every Maker Should Know

By Grace Whitlock · Fact-checked by Hugo Lindgren · Published November 13, 2026

Logic chips were the biggest product category in the 2025 semiconductor market, with $299.5 billion in sales in the revised figures from the Semiconductor Industry Association (SIA) and World Semiconductor Trade Statistics (WSTS). The same name also covers the $0.50 74HC00 in your parts drawer. The first half of this guide explains logic chips, how they differ from memory chips and where the market is heading. The second half is hands-on, with truth tables, a family picker, a part-number decoder and a breadboard build you can check with an Arduino or ESP32.

Contents

• Understand: What is a logic chip? · Logic chips vs memory chips · Logic chips by the numbers · A short history
• Build: The seven basic gates · Logic chips list · Logic families · Reading part numbers · Build it · Logic chip or microcontroller?
• Questions: FAQ

What is a logic chip? (Two meanings, one idea)

A chip, or integrated circuit (IC), is a set of transistors and their wiring patterned onto a small piece of silicon called a die. Hundreds of dies are made at once on a 300 mm silicon wafer, which is then cut apart. The scale range is huge: the four gates in a 74HC00 need only a small number of transistors, while Nvidia’s Blackwell GPU packs 208 billion across two dies.

A logic chip is an integrated circuit that processes digital signals. It takes inputs that are either high (1) or low (0) and produces outputs according to fixed rules, using transistors as switches. The industry uses the term for processors such as CPUs and GPUs. Makers use it for small gate ICs such as the 74HC00. The second kind is the building block of the first.

Logic chips in the industry sense

When SIA or WSTS report “logic” sales, they mean chips that compute rather than store or convert. That covers:

• CPUs, the general-purpose processors in PCs and servers.
• GPUs, the parallel processors behind graphics and most AI training.
• NPUs, the neural accelerators built into phone and laptop processors.
• FPGAs, which are arrays of logic you can reconfigure after manufacture.
• Microcontrollers (MCUs) such as the ATmega328P on an Arduino Uno.
• ASICs, custom chips built for one job, such as a network switch or a crypto-mining chip.
• SoCs (systems on chip), which put CPU cores, a GPU and peripherals on one die.

These are the chips foundries such as TSMC make on their most advanced processes.

Logic chips on your breadboard

For makers, “logic chips” usually means the 7400 series and 4000 series. These are cheap ICs that each hold a handful of gates, flip-flops, counters or shift registers. A 74HC00, for example, holds four 2-input NAND gates in a 14-pin package. Texas Instruments alone lists more than 600 logic gate functions in its current catalog.

How transistors become gates

Every logic chip is built from transistor switches. In CMOS (complementary metal-oxide-semiconductor) logic, a NAND gate uses four transistors. Two P-channel transistors connect the output to the supply, and two N-channel transistors connect it to ground. When both inputs are high, the N-channel pair conducts and pulls the output low. Any other combination lets a P-channel transistor pull the output high.

Combine thousands of gates and you get an adder. Combine billions and you get a GPU. The truth tables later in this guide work the same way inside a 2 nm processor as they do in a 1960s chip.

Logic chips vs memory chips (and ASICs, SoCs, analog)

Logic chips compute and memory chips store. DRAM holds working data and loses it when power goes off (volatile). NAND flash keeps data with the power off (non-volatile). Analog chips handle continuous signals such as audio and power, and mixed-signal chips combine both worlds.

Chip type	Job	Digital/analog	Examples	Where you’ll meet it as a maker
Logic (processor class)	Execute instructions, compute	Digital	CPU, GPU, NPU, FPGA, MCU	ATmega328P on an Uno, Broadcom SoC on a Raspberry Pi
Logic (discrete gates)	Fixed Boolean functions	Digital	SN74HC00, 74HC595, CD4011B	Glue logic, LED drivers, debouncing
DRAM	Fast working memory, volatile	Digital	DDR5, LPDDR4X, HBM	The RAM chip next to a Pi’s SoC
NAND flash	Bulk storage, non-volatile	Digital	microSD cards, SSDs, eMMC	The microSD card that boots your Pi
NOR flash / ROM	Code storage, non-volatile	Digital	SPI flash on ESP32 modules, mask ROM	Where your ESP32 sketch lives
Analog	Amplify, regulate, filter	Analog	Op-amps, LDO regulators	The 3.3 V regulator on a dev board
Mixed-signal	Bridge analog and digital	Both	ADCs, DACs, audio codecs, radio SoCs	ESP32’s Wi-Fi radio and ADC
ASIC	One fixed custom function	Usually digital	Bitcoin miners, network switch chips	Rarely, unless you buy a finished product

One common mix-up is worth correcting. ROM is non-volatile: mask ROM, EPROM and flash all keep their contents without power. RAM types such as DRAM and SRAM are volatile, and so are on-chip caches and processor registers.

Digital vs analog vs mixed-signal

Digital chips treat a voltage as one of two states, using defined logic ranges and noise margins so that small variations within each band do not change the result. Analog chips care about the exact value, such as an audio waveform or a battery voltage. Mixed-signal chips contain both. A microcontroller with a built-in ADC is technically mixed-signal, even though the industry counts most of them as logic or micro.

Where an SoC fits

An SoC is still a logic chip, just a very large one. It puts CPU cores, often a GPU or NPU, memory controllers, USB and video blocks on one die. The DRAM usually sits beside it as a separate memory chip. Sometimes it is stacked on top, but it is still a different die.

What’s inside a Raspberry Pi or ESP32 board, chip by chip

A Raspberry Pi 5 shows the split clearly:

• The Broadcom BCM2712 SoC is logic: four Arm Cortex-A76 cores plus a GPU.
• An LPDDR4X SDRAM chip is volatile memory.
• The RP1 I/O controller, designed by Raspberry Pi, is logic that handles GPIO, USB and Ethernet.
• A power management IC is analog/mixed-signal.
• The microSD card is NAND flash.

A typical ESP32 dev board is simpler. The ESP32 SoC is mixed-signal: two processor cores plus a Wi-Fi and Bluetooth radio. A separate SPI NOR flash chip stores your program. A USB-to-UART bridge such as the CP2102 or CH340 handles the USB port, and an LDO regulator provides 3.3 V. The ESP32 also has its own on-chip mask ROM holding the first-stage bootloader, which is non-volatile.

Logic chips by the numbers (2025–2026)

Logic was the largest semiconductor category in 2025, at $299.5 billion, but memory is set to overtake it in 2026. The WSTS Spring 2026 forecast, released on June 2, 2026, expects memory to more than triple to $803.9 billion while logic grows 37.3% to $411.4 billion. Both are AI-driven, but memory prices and volumes are running much further ahead.

Category	2025 actual	2026 forecast	2026 growth	2027 forecast	2027 growth
Logic	$299.5B	$411.4B	+37.3%	$522.8B	+27.1%
Memory	$230.0B	$803.9B	+249.5%	About $1.06T	About +32%
Total market	About $796B	About $1.51T	+89.9%	About $1.9T	About +27%

All figures: WSTS Spring 2026 forecast (June 2026). SIA’s July 2026 State of the Semiconductor Industry report uses the same revised 2025 base ($795.6 billion total, logic $299.5 billion, up 38.8%), which replaces the February 2026 SIA figures ($791.7 billion total, logic $301.9 billion, memory $223.1 billion) and the Autumn 2025 WSTS forecast of about $975 billion for 2026.

Actual 2026 sales are running ahead of even that forecast. In its second-quarter update, published in August 2026, WSTS recalculated the full-year 2026 market at about $1,655 billion, with memory now expected to grow 302%. WSTS describes these as calculations based on actual Q2 data, not a new forecast. SIA then reported third-quarter 2026 sales of $517.7 billion, up 24.1% from the second quarter and the first quarter in history above $500 billion.

Why memory is outgrowing logic in 2026

AI accelerators are logic chips, but each one is surrounded by stacks of high-bandwidth memory (HBM). WSTS names AI infrastructure, HBM and accelerated computing as the main drivers. Its 2027 outlook keeps both categories growing fast, with memory up 32% and logic up 27%.

So logic is still growing faster than in almost any year in its history. Memory has simply run further ahead.

The 2 nm era: what GAA transistors are

TSMC confirmed that its N2 process entered volume production in the fourth quarter of 2025, in Taiwan. N2 is TSMC’s first node to use gate-all-around (GAA) nanosheet transistors, in which the gate wraps the channel on all four sides instead of three. TSMC claims a 10–15% speed gain at the same power, or 25–30% lower power at the same speed, compared with N3E. N2P and A16 are scheduled for volume production in the second half of 2026.

“2 nm” is a node name, not a literal feature size. It still means billions of the same switch-based gates you are about to wire by hand.

The seven basic logic gates, with truth tables

Seven gates cover all of digital logic: AND, OR, NOT, NAND, NOR, XOR and XNOR. Each has a standard symbol, a Boolean expression and a truth table that lists the output for every input combination. In the table below, the truth table column gives output Y for inputs AB = 00, 01, 10 and 11, in that order.

Gate	Symbol	Boolean	Truth table (A,B → Y)	74HC part	CD4000 part
AND	D-shaped body	Y = A·B	00→0, 01→0, 10→0, 11→1	74HC08	CD4081B
OR	Curved shield body	Y = A + B	00→0, 01→1, 10→1, 11→1	74HC32	CD4071B
NOT	Triangle with output bubble	Y = A̅	0→1, 1→0	74HC04	CD4069UB
NAND	AND body with output bubble	Y = (A·B)̅	00→1, 01→1, 10→1, 11→0	74HC00	CD4011B
NOR	OR body with output bubble	Y = (A + B)̅	00→1, 01→0, 10→0, 11→0	74HC02	CD4001B
XOR	OR body with extra input curve	Y = A ⊕ B	00→0, 01→1, 10→1, 11→0	74HC86	CD4070B
XNOR	XOR body with output bubble	Y = (A ⊕ B)̅	00→1, 01→0, 10→0, 11→1	74HC7266	CD4077B

Everyday analogies help them stick:

• AND is a car that starts only with the key turned and the brake pressed.
• OR is a doorbell with buttons at the front and the back.
• NOT is a warning light that turns on when the door switch is NOT closed.
• XOR is a hallway light with a switch at each end: flipping either one changes the state.

NAND and NOR: the universal gates

NAND is called universal because you can build every other gate from NAND gates alone:

• NOT: tie both inputs together. (A·A)̅ = A̅.
• AND: follow a NAND with a NAND wired as NOT.
• OR: invert each input with a NAND, then NAND the results. By De Morgan’s law, (A̅·B̅)̅ = A + B.

NOR is universal in the same way. This is why one 74HC00 is enough to learn the whole truth table set, and why the build below uses it.

XOR in adders and parity

XOR outputs 1 when the inputs differ. That makes it the “sum” bit of a binary adder: 1 + 1 = 0 carry 1, and the carry comes from an AND gate. A half adder is just one XOR plus one AND. Chain XOR gates across a byte and you get a parity bit, the simplest form of error detection used on serial links.

Logic chips list: the 74-series and 4000-series ICs worth owning

A useful parts drawer needs about a dozen chips: the basic gates, a Schmitt-trigger inverter, a flip-flop, a shift register, a decoder, a counter and a level translator. They cost very little, and together they cover most of the glue-logic jobs that come up in Arduino and Raspberry Pi projects.

Part	What it does	Project idea
74HC00	Quad 2-input NAND	Learn every gate; SR latch
74HC02	Quad 2-input NOR	SR latch for a set/reset alarm
74HC04	Hex inverter	Invert an active-low enable signal
74HC08 / 74HC32	Quad AND / quad OR	Combine two sensor conditions
74HC86	Quad XOR	Half adder, parity checker
74HC14	Hex Schmitt-trigger inverter	Button debouncing, cleaning noisy signals
74HC74	Dual D flip-flop	Divide-by-2 clock, toggle on button press
74HC595	8-bit serial-in, parallel-out shift register	Drive 8 LEDs from 3 GPIO pins
74HC138	3-to-8 line decoder	Select one of 8 chips or LEDs
CD4017B	Decade counter with 10 decoded outputs	LED chaser clocked by a 555 timer
74LVC245A	Octal bus transceiver, 5 V-tolerant inputs	Bring 5 V signals into a 3.3 V board
74LVC1G series	Single gates in tiny packages	One-gate fixes on a custom PCB

Gates

Buy the six basic gate chips in the same family, ideally 74HC, so they work together without any thought about levels. A quad NAND and a hex inverter cover most quick fixes. The 74HC14 deserves special mention. Its Schmitt-trigger inputs have hysteresis, so a slow or bouncing edge produces one clean transition instead of a burst.

Flip-flops, counters and shift registers

These chips remember state, which plain gates cannot do. The 74HC74 stores one bit per flip-flop on each clock edge. The CD4017B counts pulses and lights one of ten outputs in turn. The 74HC595 is probably the most used logic chip in hobby projects: three GPIO pins clock in a byte and latch it onto eight outputs, and you can cascade chips for 16, 24 or more outputs. It is a cheap way to drive LED arrays or the enable lines of motor drivers when you are building with motors and servos.

Buffers and level shifters

Buffers strengthen or isolate signals. Level shifters translate between voltage domains. The 74LVC family matters here because its inputs tolerate 5.5 V even when the chip runs at 3.3 V. That makes it the clean way to bring a 5 V signal into a 3.3 V microcontroller.

Logic families explained: TTL, 74HC, 74HCT, 74LVC, CD4000

A logic family is a set of chips that share a process technology, supply range and input thresholds. The function number stays the same across families, so a 74LS00, 74HC00 and 74HCT00 are all quad NANDs. The letters in the middle decide whether that NAND will work with your board.

Family	Technology	Supply range	Speed example	Works with 5 V Arduino?	Works with 3.3 V ESP32/Pi?	Notes
74LS	Bipolar TTL	4.75–5.25 V	Fast, but draws far more current than CMOS	Yes	No (needs 5 V)	Legacy; Ben Eater’s 8-bit computer kit uses it
74HC	CMOS	2–6 V	74HC00: about 9 ns at 4.5 V, about 45 ns at 2 V (typical)	Yes	Yes, powered at 3.3 V	Best all-rounder; inputs need 3.15 V high at 4.5 V
74HCT	CMOS, TTL-level inputs	4.5–5.5 V	Similar to HC at 5 V	Yes	Not as a 3.3 V chip	Input high threshold 2 V; good 3.3 V-to-5 V up-shifter
74HCS	CMOS, Schmitt inputs on every gate	2–6 V	Similar to HC	Yes	Yes	Tolerates slow or noisy edges; mostly surface-mount
74LVC	Low-voltage CMOS	1.65–3.6 V (multi-gate); 1.65–5.5 V (single-gate 1G parts)	Faster than HC at 3.3 V	Single-gate 1G parts only	Yes	5 V-tolerant inputs; ideal for 5 V to 3.3 V
CD4000B	CMOS	3–18 V	Slowest here; faster at higher voltage	Yes	Yes	Wide supply; great for 9 V and 12 V circuits

The speed figures come from datasheets, and they show that supply voltage changes the speed. TI’s SN74HC00 datasheet gives about 9 ns typical at 4.5 V and about 45 ns at 2 V. For timing calculations, use the guaranteed maximum, which is 23 ns at 4.5 V across the 74-grade temperature range.

Picking a family for 5 V boards

On an Arduino Uno or Mega running at 5 V, 74HC is the default. It runs at 5 V, its outputs swing almost rail to rail, and its inputs accept the Uno’s 5 V GPIO directly.

Choose 74HCT when a 5 V circuit has to accept signals from 3.3 V or old TTL parts. Its 2 V input-high threshold reads 3.3 V as a clean 1. A 74HC at 4.5 V needs at least 3.15 V, so a 3.3 V signal clears that limit by only a small margin.

Picking a family for 3.3 V boards

On an ESP32, Raspberry Pi or Raspberry Pi Pico, power the logic chip from the 3.3 V rail. Then its outputs can never exceed 3.3 V. 74HC runs happily at 3.3 V, and 74LVC is designed for it.

74HCT is the wrong buy here. Its datasheet supply range is 4.5–5.5 V, so on a 3.3 V rail it is out of spec, and its TTL-level inputs only make sense in a 5 V system. If you run 74HCT at 5 V next to a 3.3 V board, its 5 V outputs can damage the board’s GPIO pins. Raspberry Pi GPIO pins are not 5 V tolerant.

Mixing families safely

You can mix 4000-series and 74HC chips in one circuit, but sharing a supply voltage alone does not guarantee compatibility: check both supply ranges and the input and output voltage thresholds. That supply must be within both ranges, so 5 V is the usual meeting point. At 5 V, CMOS output levels are compatible between the two families. Remember that the CD4000 parts are much slower and weaker at driving loads.

Never feed a CD4000 output running at 12 V into a 74HC input running at 5 V. Use a level shifter or a resistor divider designed for the signal speed.

How to read a logic chip part number

A logic part number reads left to right: manufacturer prefix, temperature grade, family, function number and package. Once you know the pattern, SN74HC00N tells you the maker, temperature range, family, function and package at a glance.

Segment	SN74HC00N	Meaning
Prefix	SN	Texas Instruments
Temperature grade	74	Commercial/industrial range (54 = military range)
Family	HC	High-speed CMOS
Function	00	Quad 2-input NAND
Package	N	14-pin plastic DIP, breadboard-friendly

TI’s SN74HC00 is rated from -40 °C to +85 °C, which is why “74” today often means industrial range rather than strictly commercial.

Now try CD4011BE:

• CD is the 4000-series prefix that dates back to RCA’s original CMOS line. TI makes these parts today.
• 40 marks the 4000 series.
• 11 is the function: quad 2-input NAND, the same job as a 74HC00 with a different pinout.
• B is the buffered-output version, rated for 3–18 V. The unbuffered CD4011UB shares that range. The older CD4011A was rated 3–12 V.
• E is TI’s suffix for plastic DIP on CD4000 parts.

Package codes: DIP vs SOIC vs TSSOP

TI suffix	Package	Pin pitch	Breadboard?
N (E on CD4000)	PDIP	2.54 mm	Yes
D (M on CD4000)	SOIC	1.27 mm	With adapter
DB	SSOP	0.65 mm	With adapter
PW	TSSOP	0.65 mm	With adapter

A trailing R, as in SN74HC00DR, means tape and reel, which is packaging for assembly machines. The chip inside is the same. At the extreme end, TI makes logic gates in SON packages only 0.8 mm × 0.8 mm. Those are for phones, not breadboards.

Same function, different makers

The function number is shared across manufacturers. TI’s SN74HC00N, onsemi’s MC74HC00A and Nexperia’s 74HC00D are all quad NANDs with the same pinout. Only the prefix and package codes differ. Check the datasheet’s package section before you order, because suffix letters are not standard between companies.

Build it: your first logic chip circuit

This build wires a 74HC00 so that one gate is a NAND and a second gate turns it into an AND. An Arduino drives the inputs and reads the outputs, so the serial monitor prints a truth table you can compare against the table above. A variation then uses all four gates to make an OR.

Parts list

Qty	Part	Purpose
1	SN74HC00N (DIP-14)	Four NAND gates
1	Arduino Uno (5 V) or ESP32 dev board (3.3 V)	Drives inputs, reads outputs
1	100 nF ceramic capacitor	Decoupling across VCC and GND
2	10 kΩ resistors	Pull-downs so inputs never float
2	LEDs plus 2 × 1 kΩ resistors	Show the two outputs
1	Breadboard and jumper wires	Assembly

Pinout and wiring table

The pin numbers below are for a standard 14-pin quad-gate package. Pin 1 is to the left of the notch (or next to the dot) when you look down on the chip, and the numbers run counter-clockwise. On the 74HC00, pin 7 is GND and pin 14 is VCC. Gate 1 uses pins 1, 2 → 3; gate 2 uses 4, 5 → 6; gate 3 uses 9, 10 → 8; gate 4 uses 12, 13 → 11.

From	To	Purpose
Arduino 5V (ESP32: 3V3)	74HC00 pin 14 (VCC)	Chip power
Arduino GND	74HC00 pin 7 (GND)	Ground
100 nF capacitor	Pin 14 to pin 7, as close as possible	Decoupling
Arduino D2 (ESP32: GPIO16)	Pin 1 (1A)	Input A
Arduino D3 (ESP32: GPIO17)	Pin 2 (1B)	Input B
10 kΩ resistor	Pin 1 to GND	Pull-down for A
10 kΩ resistor	Pin 2 to GND	Pull-down for B
Pin 3 (1Y)	Pins 4 and 5 (2A, 2B)	Gate 2 becomes NOT, giving AND
Pin 3 (1Y)	Arduino D4 (ESP32: GPIO18)	Read NAND output
Pin 6 (2Y)	Arduino D5 (ESP32: GPIO19)	Read AND output
Pin 3 (1Y)	1 kΩ resistor, then LED anode; LED cathode to GND	NAND indicator
Pin 6 (2Y)	1 kΩ resistor, then LED anode; LED cathode to GND	AND indicator
Pins 9, 10, 12, 13	GND	Unused inputs tied low

The sketch

// 74HC00 truth-table checker for Arduino Uno
// For an ESP32: set pins to 16, 17, 18, 19 and use Serial.begin(115200)

const uint8_t PIN_A    = 2;  // to 74HC00 pin 1
const uint8_t PIN_B    = 3;  // to 74HC00 pin 2
const uint8_t PIN_NAND = 4;  // from 74HC00 pin 3
const uint8_t PIN_AND  = 5;  // from 74HC00 pin 6

void setup() {
  Serial.begin(9600);
  pinMode(PIN_A, OUTPUT);
  pinMode(PIN_B, OUTPUT);
  pinMode(PIN_NAND, INPUT);
  pinMode(PIN_AND, INPUT);
  Serial.println(F("A B | NAND AND | check"));
}

void loop() {
  for (uint8_t i = 0; i < 4; i++) {
    uint8_t a = (i >> 1) & 1;
    uint8_t b = i & 1;
    digitalWrite(PIN_A, a ? HIGH : LOW);
    digitalWrite(PIN_B, b ? HIGH : LOW);
    delay(5);  // far longer than the gate needs

    int yNand = digitalRead(PIN_NAND);
    int yAnd  = digitalRead(PIN_AND);
    bool ok = (yNand == !(a && b)) && (yAnd == (a && b));

    Serial.print(a); Serial.print(' '); Serial.print(b);
    Serial.print(F(" |  ")); Serial.print(yNand);
    Serial.print(F("    ")); Serial.print(yAnd);
    Serial.println(ok ? F("   | OK") : F("   | CHECK WIRING"));
    delay(1000);
  }
  Serial.println();
}

You should see NAND read 1, 1, 1, 0 and AND read 0, 0, 0, 1. The two LEDs should mirror those values.

How it works

Gate 1 computes (A·B)̅. Gate 2 has both inputs tied to that result, so it acts as an inverter and outputs A·B. The 10 kΩ pull-downs hold the inputs low while the Arduino resets, because its pins float as inputs during boot.

OR variation: all four gates in use

The OR version uses gates 3 and 4 as inverters on A and B, then feeds them into gate 1, so pins 9, 10, 12 and 13 stop being unused inputs. Those pins are tied to GND in the first build, and an Arduino output driven HIGH into a pin wired to ground is a short. Clear the old links first.

1. Unplug the USB cable. Remove the GND links from pins 9, 10, 12 and 13, and the pull-downs from pins 1 and 2. Disconnect D2 and D3 from pins 1 and 2.
2. Bridge pins 9 and 10, connect them to D2 (input A) and fit a 10 kΩ pull-down from pin 9 to GND. Gate 3 now outputs NOT A on pin 8.
3. Bridge pins 12 and 13, connect them to D3 (input B) and fit a 10 kΩ pull-down from pin 12 to GND. Gate 4 now outputs NOT B on pin 11.
4. Wire pin 8 to pin 1 and pin 11 to pin 2. Pins 1 and 2 are now driven by gate outputs, so they need no pull-downs.
5. Leave pin 3 to pins 4 and 5, pin 3 to D4 and pin 6 to D5 as they were. Gate 1 now outputs A OR B on pin 3, and gate 2 inverts it into NOR on pin 6.

From	To	Purpose
Arduino 5V (ESP32: 3V3), GND, 100 nF	Pins 14 and 7	Power and decoupling, unchanged
Arduino D2 (ESP32: GPIO16)	Pins 9 and 10 (3A, 3B)	Input A
Arduino D3 (ESP32: GPIO17)	Pins 12 and 13 (4A, 4B)	Input B
10 kΩ resistor	Pin 9 to GND	Pull-down for A
10 kΩ resistor	Pin 12 to GND	Pull-down for B
Pin 8 (3Y)	Pin 1 (1A)	NOT A into gate 1
Pin 11 (4Y)	Pin 2 (1B)	NOT B into gate 1
Pin 3 (1Y)	Pins 4 and 5, Arduino D4, LED	A OR B output
Pin 6 (2Y)	Arduino D5, LED	A NOR B output

The sketch’s “NAND” column now reads the OR output (0, 1, 1, 1) and its “AND” column reads NOR (1, 0, 0, 0). To make the check column pass, replace the ok line with:

bool ok = (yNand == (a || b)) && (yAnd == !(a || b));

Common mistakes: floating inputs, missing VCC, wrong family

• Floating inputs. An unconnected CMOS input picks up noise, produces random outputs and can draw extra current. Every input needs a defined level.
• Missing VCC or swapped power pins. The chip may appear to work weakly, powered through its input protection diodes. Check pins 14 and 7 first.
• Wrong family. A 74HCT00 on an ESP32’s 3.3 V rail is out of spec. A 74HC00 powered at 5 V will push 5 V into ESP32 GPIO pins.
• Leftover ground links. When you reuse a pin that was tied to GND as an input, remove the GND wire before connecting a GPIO output to it.
• No decoupling capacitor. Fast edges cause supply glitches, and these show up as false triggers in flip-flops and counters.
• Pinout assumptions. The 74HC02 NOR has a different pin order from the 74HC00, and CD4000 pinouts differ again. Read the datasheet for each chip.

Logic chip or microcontroller? When each wins

Use a logic chip when the job is a fixed rule that needs to happen instantly, cheaply and without firmware. Use a microcontroller when the behavior may change, involves timing or needs communication. Most real projects use both: the microcontroller for the brains and a few gates for the glue between parts.

Where gate chips still win:

• Speed. A 74HC gate responds in nanoseconds. Firmware polling a pin takes microseconds, and that assumes the code is not busy elsewhere.
• No firmware to crash. An emergency-stop interlock built from gates keeps working if the microcontroller hangs.
• Glue logic. Inverting an active-low enable pin, combining two chip-select lines or gating a motor driver’s enable takes one chip and no code.
• Debouncing. An RC filter into a 74HC14 gives a clean edge without spending CPU time.
• Level shifting. A 74LVC245A translates eight lines from 5 V to 3.3 V at once.
• Pin expansion. A 74HC595 or 74HC138 multiplies your general purpose input/output pins.

Where a microcontroller wins: anything with timing sequences, serial protocols, analog readings or behavior you want to change later. Ten gate chips doing what one $3 microcontroller could do is a poor trade in board space and wiring time.

There is also a fair argument against learning discrete logic at all: very few new commercial designs use whole boards of it. The counter-argument is stronger, though. Building Ben Eater’s breadboard 8-bit computer from 74LS chips teaches more about how a CPU works than any datasheet. The same gates show up in every SoC, FPGA and microcontroller block diagram you will ever read.

A short history: from the 1964 7400 to 2 nm processors

The 7400 series began in October 1964, when Texas Instruments released the 7400 quad 2-input NAND in a military-grade metal flat package. The plastic DIP version that hobbyists know followed in the third quarter of 1966. The original “54” and “74” prefixes still mark temperature grade. 54 means the full military range, and 74 is the commercial/industrial part.

Those first parts were bipolar TTL. Later bipolar families such as 74LS cut power, and the CMOS 4000 series from RCA offered tiny standby current and a wide supply range. High-speed CMOS brought both together. TI’s SN74HC00 datasheet carries an original date of December 1982, and 74HC remains the default maker family. Newer lines such as 74HCS and 74LVC added Schmitt inputs and low-voltage operation.

The same NAND function now exists as billions of GAA transistors inside chips made on processes such as TSMC’s N2. You can still buy a 74HC00 with the same logic function as the 1964 original.

FAQ

What are logic chips?

Logic chips are integrated circuits that process digital signals, making decisions on 1s and 0s with transistor switches. In industry data, the term covers CPUs, GPUs, NPUs, FPGAs, microcontrollers and ASICs. For makers, it usually means 7400-series and 4000-series gate ICs such as the 74HC00.

What is a chip in a computer?

A chip is an integrated circuit: transistors and wiring patterned onto a silicon die cut from a wafer. A computer contains several kinds. The CPU and GPU are logic chips, the RAM is DRAM memory, and the SSD is NAND flash. The logic vs memory table above maps each type to its job and to where it appears on a Raspberry Pi or ESP32 board.

What is the difference between logic chips and memory chips?

Logic chips compute, while memory chips store data. DRAM is volatile working memory that loses its contents without power. NAND flash is non-volatile storage used in SSDs and microSD cards. A computer needs both, and they are usually separate dies.

What are examples of logic chips?

Processor-class examples include an Intel or AMD CPU, an Nvidia GPU, the Broadcom BCM2712 in a Raspberry Pi 5 and the ATmega328P in an Arduino Uno. Discrete examples include the SN74HC00 NAND, 74HC14 Schmitt inverter, 74HC595 shift register and CD4011B NAND.

Is a CPU a logic chip?

Yes. A CPU is the classic logic chip, built from billions of transistor gates that execute instructions. SIA and WSTS count CPUs in their logic category.

Is a GPU a logic chip or a memory chip?

A GPU is a logic chip. The graphics card or AI accelerator it sits on also carries separate memory chips, such as GDDR or HBM, and those count as memory.

How big is the logic chip market?

Logic sales were about $300 billion in 2025, according to SIA and WSTS figures. The WSTS Spring 2026 forecast puts 2026 logic sales at $411.4 billion and 2027 at $522.8 billion. Memory is forecast to pass logic in 2026.

What are logic chips used for?

They run every digital system, from phones and data center AI servers to industrial controllers and cars. In maker projects, discrete logic chips handle glue logic, LED driving, pin expansion, debouncing and level shifting.

Are logic gate ICs still used today?

Yes. TI alone lists more than 600 logic gate functions, many in tiny surface-mount packages used on modern boards for glue logic and level translation. Through-hole DIP versions of classics such as the SN74HC00N are still made for breadboard work.

What is the difference between 74HC and 74HCT?

74HC runs from 2 V to 6 V, and its input thresholds scale with supply voltage. 74HCT runs only from 4.5 V to 5.5 V and has TTL-level inputs, with a 2 V input-high threshold. HCT is the better pick when a 5 V circuit has to read 3.3 V or old TTL signals.

Can I use 74HC chips with a 3.3 V ESP32 or Raspberry Pi?

Yes, if you power the 74HC chip from the board’s 3.3 V rail. Its outputs then stay at 3.3 V and are safe for the GPIO pins. It runs slower than at 5 V, but still far faster than any GPIO loop.

What is the difference between 7400 and 4000 series logic chips?

The 7400 series started as TTL and now mostly means CMOS families such as 74HC, usually running at 5 V or 3.3 V. The 4000 series has been CMOS from the start, runs from 3 V to 18 V (B versions) and is slower. The same function often has a different number and pinout in each series: the 74HC00 and CD4011B are both quad NANDs.

Where can I still buy through-hole DIP logic chips?

Major distributors still stock the classic 74HC and CD4000 parts in DIP. Filter for N-suffix parts (or E for TI’s CD4000 parts). Many newer families, such as 74LVC and 74HCS, are mostly surface-mount, so for those use an SOIC-to-DIP adapter board.

A good first purchase is a 74HC00, a 74HC14 and a 74HC595. Once the NAND build on your breadboard passes the truth-table check, try driving eight LEDs from three pins with the shift register. That is the point where logic chips become part of your normal toolkit.

Notes on this article

GW

Written by Grace Whitlock

Grace writes Artoo Maker Lab's Arduino and electronics basics guides, plus sensors, modules and workshop tools like soldering irons. She explains circuits the way she would want them explained on day one, with the wiring, the numbers and the common mistakes.

Covers: Electronics Basics, Arduino

• Fact-checked by Hugo Lindgren against the sources listed below before publication.
• Published November 13, 2026

Fact-checking

• Researched from 8 sources, listed below.
• Every claim is checked by Hugo Lindgren; anything we cannot confirm is corrected, labelled or removed.

Sources (8)

1. Global Annual Semiconductor Sales Increase 25.6% to $791.7 Billion in 2025 (SIA) (semiconductors.org)
2. SIA 2026 State of the Semiconductor Industry (semiconductors.org)
3. WSTS: Global Semiconductor Market Surges Beyond 1.5T in 2026 (wsts.org)
4. WSTS Forecast Release May 2026 (wsts.org)
5. WSTS: Global Semiconductor Market records exceptional growth in Q2 2026 (wsts.org)
6. TSMC begins volume production of 2nm-class chips (Tom's Hardware) (tomshardware.com)
7. TSMC's 2nm N2 process officially enters volume production (TechSpot) (techspot.com)
8. SN74HC00 product page and datasheet (Texas Instruments) (ti.com)