NE555 Timer Pinout
DIP-8 package, top view, pin 1 at the notch. Check your board against its silkscreen before wiring power.
What each pin does
TRIG below one third of VCC starts the cycle, THRES above two thirds ends it, and DISCH empties the timing capacitor in between. RESET overrides everything when pulled low, so tie it to VCC when unused. CTRL shifts the internal thresholds and normally just wants a 10 nF capacitor to ground.
Bipolar versus CMOS
The classic bipolar NE555 runs on 4.5 to 16 V and drives 200 mA straight out of pin 3. CMOS versions (7555, TLC555) work down to 2 V and draw microamps, with a much weaker output. Both share this pinout.
Picking parts
The 555 calculator works out resistor and capacitor values for astable and monostable circuits.
Sources and datasheets
This diagram was cross-checked against the manufacturer documentation below plus at least two independent references before publishing. When they disagreed, the manufacturer won.
More boards and plugs live on the pinouts index.