NE555 Timer

Operating Voltage

4.5 V

Operating Voltage

16 V

Output Current Sink Source

200 mA

Temperature Range

0 °C

Temperature Range

70 °C

Interface

TTL-compatible output

Timing Range

microseconds to hours

Frequency Range

< 1mHz to 100kHz

Runs on a 4.5-16 V supply (per the datasheet specs) with an output that can sink/source up to 200 mA. The bipolar version is not a 3.3 V-logic part.

• Astable oscillators / clock and tone generation
• Monostable one-shot timers and debouncers
• PWM and simple pulse generation

• Decouple the supply (e.g. 100 nF) — the output switching is noisy.
• Use a 10 nF cap on the CONTROL pin if you don't drive it.
• For 3.3 V systems choose a CMOS 555 (e.g. LMC555/TLC555) instead.

• LM358 Dual Op-AmpLM358 · Texas Instruments
• ATmega328P MCUATmega328P · Microchip

Community starter examples — minimal, unofficial, and provided to get you wiring fast. Verify against the manufacturer datasheet before relying on them.

// NE555 is a standalone analog timer (no MCU needed to run it).
// This starter just READS the 555's OUT pin to measure its frequency.
#if defined(ESP32)
  #define OUT_PIN 4
#else
  #define OUT_PIN 2
#endif

void setup() {
  Serial.begin(115200);
  pinMode(OUT_PIN, INPUT);
}

void loop() {
  unsigned long high = pulseIn(OUT_PIN, HIGH);   // microseconds
  unsigned long low  = pulseIn(OUT_PIN, LOW);
  if (high + low > 0) {
    float freq = 1000000.0 / (high + low);
    Serial.print(freq); Serial.println(" Hz");
  }
  delay(500);
}

# NE555 timer - measure its OUT frequency (ESP32) — community starter example
# The 555 runs on its own R/C network; here we just read OUT on a GPIO.
from machine import Pin, time_pulse_us
import time

out = Pin(4, Pin.IN)   # 555 OUT -> GPIO4

while True:
    high = time_pulse_us(out, 1, 1000000)
    low  = time_pulse_us(out, 0, 1000000)
    if high > 0 and low > 0:
        print(1_000_000 / (high + low), "Hz")
    time.sleep(0.5)