NE555 Precision Timer
The classic precision timing circuit capable of producing accurate time delays or oscillation in astable or monostable modes.
Aliase:555 Timer, LM555, SE555
DIP-8 Top View
8 Pins
Pin-Tabelle8
| Pin | Signal / Name | Typ | Alternative Funktionen |
|---|---|---|---|
| 1 | GND | Ground | System Ground (0V) |
| 2 | TRIG | Analog | Trigger Input — when voltage falls below 1/3 VCC, output goes HIGH and timing begins; active-low pulse input |
| 3 | OUT | Digital | Timer Output — HIGH during timing period; can source/sink up to 200mA; connect LED/relay directly |
| 4 | RESET | Digital | Reset (Active Low) — forces output LOW and discharge transistor ON regardless of other inputs; tie to VCC if unused |
| 5 | CTRL | Analog | Control Voltage — direct access to internal 2/3 VCC voltage divider; connect 10nF cap to GND to reduce noise; can be used to modulate threshold |
| 6 | THR | Analog | Threshold — when voltage rises above 2/3 VCC, output goes LOW and discharge transistor turns ON |
| 7 | DISCH | Digital | Discharge — open-collector switch connects timing capacitor to GND during output LOW phase; connect to RC timing network |
| 8 | VCC | Power | +4.5V to +16V Supply — add 100nF bypass cap to GND near pin |