Astable Multivibrator using TransistorsAim: To Observe the ON & OFF states of transistor in an Astable Multivibrator.

Apparatus required:Astable monostable using transistors kitCro & bnc connecting cable.Theory :Astable multivibrator : An Astable Multivibrator has two quasi stable states and itkeeps on switching between these two states by itself . No external triggering signal isneeded. The astable multivibrator cannot remain indefinitely in any one of the two states.The two amplifier stages of an astable multivibrator are regenerative across coupled bycapacitors. The astable multivibrator may be to generate a square wave of period, 1.38RC.

Procedure1. Calculate the theoretical frequency of oscillations of the circuit.2. Connect the circuit as per the circuit diagram shown in Fig 1.3. Observe the voltage wave forms at both collectors of two transistors simultaneously.4. Observe the voltage wave forms at each base simultaneously withcorresponding collector voltage as shown in Fig 3.5. Note down the values of wave forms carefully.6. Compare the theoratical and practical values.

Calculations:Theoretical Values:RC= R1C1+ R2C2

Time Period, T = 1.368RCR=15K, C=0.01Uf