555 Timer IC

The 555 Timer IC is a super versatile integrated circuit used for timing, pulse generation, and oscillator functions.

Key Features of NE555:

• Operates from +4.5V to +15V
• Can source or sink up to 200mA
• Timing from microseconds to hours
• Works in three main modes:
• Astable (free-running oscillator)
• Monostable (one-shot pulse)
• Bistable (flip-flop)

???? Pinout (8-pin DIP):

      +--------+
  GND |1     8| VCC
 TRIG |2     7| DISCH
 OUT  |3     6| THRES
  RES |4     5| CTRL
      +--------+

PinNameDescription

1 GND Ground

2 TRIG Trigger input

3 OUT Output

4 RESET Reset (active low)

5 CTRL Control voltage (often unused)

6 THRES Threshold

7 DISCH Discharge

8 VCC Supply voltage (+4.5V to +15V)

Common Configurations:

1. Astable Mode (Oscillator)

• Continuously generates square waves
• Used in blinking LEDs, tone generation, clock signals

Basic formula:

Frequency ≈ 1.44 / ((R1 + 2*R2) * C1)
Duty Cycle ≈ (R1 + R2) / (R1 + 2*R2)

2. Monostable Mode (One-shot pulse)

• Produces a single pulse when triggered
• Great for timers or debounce circuits

Pulse Width:

T = 1.1 * R * C

3. Bistable Mode (Flip-flop)

• Stays in one state until triggered
• Useful in switch toggles, memory elements

Projects:

• LED blinkers
• Tone generators
• PWM controllers
• Timers and delay circuits
• Frequency generators

Origin:- China

Brand:- Generic