Hi,
I was suppose to construct this circuit using Multisim
where Vs is sinusoidal signal 0.1Vpeak, 10kHz.
This is my simulation circuit from Multisim
This is the result of oscilloscope for both signal waveform, Vs and Vc.
As you can see from the oscilloscope, the output voltage is amplified, with the voltage gain around -5.2 V/V
The problem is, if I increase the amplitude of the input signal source,for example from Vp=0.1 to Vp=0.5
It will have this weird distortion, and the output wave seems to have shift down.Moreover the gain is reduced!
I have research about the BJT again. In my opinion, I think this is because the bias voltage has changed and thus the Q point also changes so it lies in cut off mode.
However , I thought the clipping will occur if the output is greater than the limit supply voltage rail which is Vcc=5V.but it clips at +1.024V.
Do I have to look at DCload line to find out the limit?
if I further increase the amplitude, the gain reduces more but the clipping still remains at around+1.90V and the negative part of the output wave also starts to clip.
To find the upper -3db frequency, I have to find the bandwidth of amplifier.
So what I do is,
take the voltage gain(-5.2V/V) multiply by 0.707
which is -3.6764V/V
Then using the new voltage gain, multiply by the 0.1Vp
which is -0.36764V.
So my output waveform should get max peak -0.36744 V right?then just check the period for the wave,then proceed to find frequency
But If I change the frequency on the ac voltage source, the output remain same just the wave is stretched out.
If I try to use bode plotter,
The straight constant line is not there?so I cant get the bandwidth.
Any inputs or comment for this matter is appreciated.Please correct me if I have stated the wrong theory or if there is something wrong for my circuit
Thanks again for your help and patience.
I was suppose to construct this circuit using Multisim
where Vs is sinusoidal signal 0.1Vpeak, 10kHz.
This is my simulation circuit from Multisim
This is the result of oscilloscope for both signal waveform, Vs and Vc.
As you can see from the oscilloscope, the output voltage is amplified, with the voltage gain around -5.2 V/V
The problem is, if I increase the amplitude of the input signal source,for example from Vp=0.1 to Vp=0.5
It will have this weird distortion, and the output wave seems to have shift down.Moreover the gain is reduced!
I have research about the BJT again. In my opinion, I think this is because the bias voltage has changed and thus the Q point also changes so it lies in cut off mode.
However , I thought the clipping will occur if the output is greater than the limit supply voltage rail which is Vcc=5V.but it clips at +1.024V.
Do I have to look at DCload line to find out the limit?
if I further increase the amplitude, the gain reduces more but the clipping still remains at around+1.90V and the negative part of the output wave also starts to clip.
To find the upper -3db frequency, I have to find the bandwidth of amplifier.
So what I do is,
take the voltage gain(-5.2V/V) multiply by 0.707
which is -3.6764V/V
Then using the new voltage gain, multiply by the 0.1Vp
which is -0.36764V.
So my output waveform should get max peak -0.36744 V right?then just check the period for the wave,then proceed to find frequency
But If I change the frequency on the ac voltage source, the output remain same just the wave is stretched out.
If I try to use bode plotter,
The straight constant line is not there?so I cant get the bandwidth.
Any inputs or comment for this matter is appreciated.Please correct me if I have stated the wrong theory or if there is something wrong for my circuit
Thanks again for your help and patience.