555 timer (NE555)
NE555 timer · 4.5–16 V · output sources or sinks 200 mA · thresholds at ⅓ and ⅔ V_CC (set by the CTRL pin)
Try it on the benchThe lab drops it on an empty bench and opens its datasheet card.
Typical part: NE555 (DIP-8)
Pins
- GND
- TRIG (start below ⅓ V_CC)
- OUT
- RESET (active low)
- CTRL (⅔ V_CC)
- THR (stop above ⅔ V_CC)
- DIS (discharge)
- VCC
Ratings and limits
| Supply | 4.5–16 V |
|---|---|
| Output | sources or sinks 200 mA |
| Thresholds | ⅓ and ⅔ V_CC |
How to use it
Astable: f = 1.44 / ((R1 + 2R2)·C). Monostable: t = 1.1·R·C. LED flashers, PWM, timers, debouncers.
Lessons and builds that use it
- 555 astable (LED flasher)
- 555 monostable (one-shot timer)
- Charge-pump inverter: a negative rail
- 555 delay-off timer with relay (build)
- PWM fan or LED dimmer (build)
- 12. 555 timer: stay on after they pass (build)
- 13. Buzzer: an alarm mode (build)
- 14. Solar: the light runs off-grid (build)