Spark Logic

74HC04 connection guide

Wire and test the TI SN74HC04 as an inverter or buffer.

Connect and bypass the supply

With power off, connect a regulated 4.5 V supply to 14 VCC and its return to 7 GND. Fit a 100 nF ceramic capacitor directly across these pins with short leads. Connect the logic source and meter grounds to the same return.

4.5 V to pin 14, return to pin 7 and 100 nF across both pins4.5 VReturn100 nF14 VCC7 GND

Finish the logic wiring below before powering up. Verify 4.5 V at pin 14 with the meter common at pin 7.

1 1A 2 1Y 3 2A 4 2Y 5 3A 6 3Y 7 GND Used in this circuit
14 VCC Used in this circuit13 6A 12 6Y 11 5A 10 5Y 9 4A 8 4Y
Top view · Pin 1 at upper left · Schematic outline

Choose the output polarity

Connect a fast CMOS source that swings from 0 V to VCC to 1A (pin 1). Jumper 1Y (pin 2) to 2A (pin 3). Read the result at 2Y (pin 4).

Two-gate buffer. Input pin 1, output pin 4. Unused inputs 5, 9, 11, 13 connect to pin 7.IN → 1 1A4 2Y → OUT2 1Y → 3 2A5 3A9 4A11 5A13 6A7 GND

Tie unused inputs 5, 9, 11, 13 to GND and leave their outputs open. Apply the logic signal only while the IC is powered.

1 1A Used in this circuit2 1Y Used in this circuit3 2A Used in this circuit4 2Y Used in this circuit5 3A Used in this circuit6 3Y 7 GND Used in this circuit
14 VCC 13 6A Used in this circuit12 6Y 11 5A Used in this circuit10 5Y 9 4A Used in this circuit8 4Y
Top view · Pin 1 at upper left · Schematic outline
Arrows show signal direction between paired pins.

Check both logic states

Input (pin 1)Output (pin 4)
LOW (0 V)LOW
HIGH (VCC)HIGH

Measure the settled output relative to pin 7 with a high-impedance meter (for example, 10 MΩ). At 4.5 V and an output load of 20 µA or less, expect LOW ≤ 0.1 V and HIGH ≥ 4.4 V. If either state is wrong, verify the supply and input swing at the IC before checking the pin numbering and jumpers. See the electrical limits.

Package and documents

TI package code D · 8.7 × 3.9 mm nominal body · 1.27 mm lead pitch. Use TI’s package outline for footprint dimensions and tolerances.

Order codes use the SN74HC04 prefix. Suffixes for this package in TI’s 23 October 2026 addendum: DR, DR.A, DRG3, DRG3.A, DRG4, DRG4.A; D, DT (obsolete).

Circuit references: §§ 5, 6.3, 6.5, 8.3, 9 and 10.