Astable multivibrator using 555 Timer IC

Components Required:

1.  555 Timer IC & their datasheet (download here)
2. Resistor:- 1K, 1M, 100K.
3. Capacitor:- .1uF(104-Ceramic), 1uF or 2uF (Electrolytic)
4. 9V battery as a dc power source
5. Breadboard, Wires, LED.

Circuit description:

Astable multivibrator circuit

Here R3=470ohm or 1K for LED, C1=0.1uF or 0.01uF.

 

Practical Result:

LED ON time can be calculated using

T_high = 0.7*(R1+R2)*C2

LED OFF timing can be calculated using

T_low = 0.7*R2*C2

Total timing can  be calculated using

T = T_high+ T_low

Frequency can be calculated using
f = 1/T