What this 74HCT quad NOR gate is for
The CD74HCT02E is a quad 2-input NOR gate from the 74HCT series — four independent gates in a single 14-pin DIP package, each with two inputs. It implements the NOR logic function (output high only when both inputs are low) and is a direct drop-in for TTL-compatible 5 V logic systems.
Supply range and temperature grade
Operates from 4.5 V to 5.5 V, which covers the standard 5 V logic rail with margin for regulation tolerance. The -55°C to 125°C temperature range is the full military-grade span — this gate works in an engine bay, a cold-storage warehouse, or a satellite payload without derating. Input logic thresholds are set for TTL compatibility: a low level below 0.8 V is guaranteed to be seen as a logic 0, and a high level above 2 V is seen as a logic 1. This means it interfaces directly with 5 V TTL outputs without a level translator.
Speed and drive capability
Maximum propagation delay is 21 ns at 4.5 V with a 50 pF load — fast enough for most 5 V logic buses running below 20 MHz. The output can source or sink 4 mA, which is sufficient to drive one or two standard TTL loads or an LED through a current-limiting resistor. Quiescent current is just 2 µA max — the gate draws almost nothing when the outputs are static, making it suitable for battery-backed or power-sensitive boards where the logic sits idle most of the time.
Package and field-fit
Housed in a 14-lead PDIP (0.300-inch body width, 7.62 mm row spacing) — the classic through-hole DIP that fits standard breadboards, protoboards, and socketed production boards. The 0.100-inch pin pitch is easy to hand-wire or rework with a basic soldering iron; no hot-air station needed. Shipped in a tube — the tubes protect the leads during handling and are compatible with automatic tube feeders on through-hole insertion machines.