Amplificator

http://everycircuit.com/circuit/4863908626563072

You need to adjust the values. Take a look at the Examples tab circuits or search for ce amp

No voltage source. An amplifier takes the energy from a DC source and modulates it into a preset AC source. The input should be sinewave, not square wave, and the biasing is wrong. Basically everything is wrong, sorry. Check some examples and try again

Actually the input he applied is itself square wave ...how can the output be sine ??????

Mas

In this circuit the transistor will be in saturation and cut off. At positive pulse it will go into saturation and when zero or less will go in cut off mode. The circuit is not biased to work in linear or amplifier mode as the base to collector junction is forward biased.

@ggundap, have you read the previews comments? Start with buggzy's first three words!

Hurz, the input pulse itself acts as a dc supply voltage to the base and the collector when ever it is at its positive peak for that time period and when zero basically without any dc voltage supply.

you need a dc source. problem solved

Actually in vacuum tubes there is a way to bias it without any external components, just an input cap. When the signal swings positive the grid acts as a diode, releasing some voltage upon the grid, and the bleeder resistor is of very high value to diacharge it. But...There's a but. This method is not used in audio amplifiers, just sinewave amplifiers, and it doesn't apply to bjt transistors, because their input impedance is quite low compared to MOSFETs or Vacuum tubes. Moreover an amplifier always needs a DC source, because that's what an amplifier basically does. Convert DC to AC, the AC being with a specific waveform you've chosen.

I have the same bug ... Do you find a solution ?