1. 555 Integrated Circuit (IC)
JC Technology
555 Integrated Circuit (IC)

2. 555 IC 8-Pin D.I.L. (Dual in Line) integrated circuit (chip)
Must be connected correctly
Notch
Dot
Pin 1 to left of dot

3. 555 IC Circuit Pin arrangement Simplifies circuit drawing
Two modes of operation:
Monostable
Astable

4. 555 IC Monostable Mode Only one stable state
Output will turn on or off for timed period
Always return to its original state
Time period
Output
Trigger

5. 555 IC
Monostable Mode
Trigger = PTB pressed – voltage drops (9v to 0V)
Signal to 555 IC to start timed period
Time period depends on value of R3 and C1
LED turns on for time period
Stable state = Off

6. 555 IC Monostable Mode Change position of output
LED turns off for time period
Stable state = On

7. 555 IC Astable Mode No stable state
Output turns on and off continuously
LED turns on/off, on/off etc

8. 555 IC Astable Mode Changing position of output
LED turns off/on, off/on etc

9. 555 IC
Astable Mode
Flashing Lights – two LEDs