05
intermediate+300 XP

555 Timer LED Blinker

Build an oscillating circuit using the iconic 555 Timer IC to blink an LED automatically.

🎯 Objective

Configure the 555 in astable mode to generate a 2Hz blink rate.

📖 Background Theory

The 555 timer in astable mode continuously oscillates between HIGH and LOW. **Timing formula:** - Time HIGH: t1 = 0.693 × (Ra + Rb) × C - Time LOW: t2 = 0.693 × Rb × C - Frequency: f = 1.44 / ((Ra + 2Rb) × C) **For ~2Hz blink with C1=10μF:** - Ra = 10kΩ, Rb = 47kΩ - f = 1.44 / ((10k + 94k) × 10μ) = 1.38 Hz ≈ 1.4 Hz flash **Connections:** - Pin 8 (VCC) → +9V - Pin 1 (GND) → GND - Pin 4 (RESET) → VCC (must be HIGH to enable) - Pins 2 and 6 connected together - Pin 3 (OUTPUT) → LED via resistor

🔧 Components You'll Use

Ic 555BatteryResistorLedGround

📋 Steps (9)

  1. 1Place 555 Timer IC, Battery, 2x Resistors, LED, and Ground
  2. 2Wire Pin 8 (VCC) to Battery +
  3. 3Wire Pin 1 (GND) to Ground
  4. 4Wire Pin 4 (RESET) to Battery +
  5. 5Connect Pins 2 and 6 together (astable mode)
  6. 6Wire Ra between VCC and Pin 7 (DISCH)
  7. 7Wire Rb between Pin 7 and Pin 2/6
  8. 8Wire Pin 3 (OUT) → 470Ω resistor → LED → GND
  9. 9Run simulation and watch the LED blink!