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NE555: Timer IC — Datasheet, Circuits & Buying Guide
NE555 guide: classic timer IC, astable/monostable circuits, applications and sourcing.
NE555 guide: classic timer IC, astable/monostable circuits, applications and sourcing.
The NE555 is the most famous timer IC in electronics history. This guide covers its operating modes and procurement.
By Vigny (深圳市华芯购电子有限公司) · Published 2026-09-27 · Data verified 2026-09-29 · Sources: manufacturer datasheets & HuaXinGou stock verification
The NE555 contains two comparators, a flip-flop and a discharge transistor, forming a timer in astable (oscillator), monostable (one-shot) and bistable modes.
In astable mode, frequency f = 1.44 / ((RA + 2RB) * C). Duty cycle and frequency are set by two resistors and one capacitor, providing square-wave clocks.
PWM generation, LED flashers, buzzer drivers, debounce circuits, timers and tone generators. The CMOS version TLC555 draws less current for battery designs.
NE555/NE555N from TI, ST and others, plus CMOS TLC555 and SA555. HuaXinGou stocks common DIP-8 and SOIC-8 variants.
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