1Pin 1 notch
2Pin 1 dot
374HC00N quad NAND gate
4Epoxy body (DIP-14) · 19.3 × 6.35 mm
5Pins (2.54 mm pitch)

Black DIP-14 body, notch and pin 1 dot, “74HC00N” text
DIP-14: body ≈ 19 × 6.4 mm, pin pitch 2.54 mm

Integrated circuits

Logic gate (74HC00)

In simple terms

What is this?

An IC with four small decision gates; if both inputs are yes, it says no.

What is it for?

Sets the output based on the inputs; you can build any logic circuit with them.

Where do you see it?

Inside computers, games and digital watch circuits.

How do you spot it?

Black IC with fourteen pins in two rows; 74HC00 is printed on top.

Caution:

Don't leave unused inputs floating; connect the supply and ground pins.

Technical definition

A CMOS logic IC containing four two-input NAND gates. The NAND output is 0 only when both inputs are 1. All other logic gates can be built from NAND gates.

Power supply2–6 V

Contents4 × NAND

PackageDIP-14

Schematic symbol IEC and ANSI differ

IEC 60617: the drawing style used in Türkiye and Europe.

Pins 10

1Gate 1 inputs (1A, 1B)Pins 1 and 2; starts top left with notch up1–2

3Gate 1 output (1Y)Pin 33

4Gate 2 inputs (2A, 2B)Pins 4 and 54–5

6Gate 2 output (2Y)Pin 66

7GNDPin 7, bottom leftGND

8Gate 3 output (3Y)Pin 8, bottom right8

9Gate 3 inputs (3A, 3B)Pins 9 and 109–10

11Gate 4 output (4Y)Pin 1111

12Gate 4 inputs (4A, 4B)Pins 12 and 1312–13

14VCCPin 14, top right; 2–6 VVCC

Features typical

Power supply: 2–6 V
Output current: ±4 mA (4.5 V, rated)
Absolute limit: ±25 mA / output
Delay: ≈7–10 ns (5 V)
Inputs: CMOS; draws no current, never left floating
Truth table: 00 → 1 · 01 → 1 · 10 → 1 · 11 → 0
Example part: 74HC00N (DIP-14)

Common mistakes

Leaving unused inputs floatingFloating CMOS inputs change randomly and draw extra current. Tie unused inputs to GND or VCC.

Overloading an output with an LEDThe output is designed for a few mA. Connect the LED with a series resistor such as 1 kΩ (≈3 mA), or drive it with a transistor.

Forgetting decouplingPut a 100 nF capacitor between VCC and GND, close to the IC; otherwise switching noise causes errors.

Test with a multimeter

Test whether this part is good with the multimeter on the measurement screen.

Take a measurement

Where it is used

Logic gate experimentsSR latch (flip-flop)Simple oscillatorDebouncing the button signal