I am trying to do a basic current gain amplifier. Everything works until I place the capacitor in series with the 10 ohm load to remove the DC offset:

I have no clue what's going on here. I tried playing with C1 value but it didn't do much. Shouldn't the output just be the input at the origin? What am I doing wrong?

Thanks

Edit: the transistor is an ideal NPN

 

The 10Ω load is far too large for the 100µF capacitor to make any difference. Try raising C1 and R5.

 

So for this circuit to drive a 4 ohm speaker I would need a giant capacitor? Like .1 Farads?

 

So for this circuit to drive a 4 ohm speaker I would need a giant capacitor? Like .1 Farads?

Guessing at part values does not generally work well for electronic design.
If you do the math for the -3dB point [C = 1/(2πRf)] it requires nearly a 2,000μF capacitor to give a -3dB rolloff into a 4 ohm load at f = 20Hz.

 

Your guess is only 50x higher than crutschow's calculated value. I've seen worse.

 

Well your problem is simple to explain.
the current (Emit + Basis) goes via 10 ohm.
open then sw then it goes via 1K so Ue goes up and when above 0,6V The xtor is switched off.
adive: measure Ue when sw is open and alter the 1K resistor

 

Haha ya, .1F was an exaggerated estimation. I'm still thinking about this problem though; if I have a DC biased audio signal and I want to send it into a 4 ohm speaker, is the only simple option a giant capacitor or is there some technique that I am missing?