I have simulate a hartley oscillator and its ouput is 4nV peak to peak. I need 6V peak to peak, any idea how to amplify it?

 

Are you sure that your oscillator output is only 4 nanovolts? How did you even find it? Some of the output has to feed back in order for oscillations to continue - that level is certainly not enough.

 

Are you sure that your oscillator output is only 4 nanovolts? How did you even find it? Some of the output has to feed back in order for oscillations to continue - that level is certainly not enough.

Now I wonder where is the location of the output.

at base before the coupling capacitor:
V peak to peak 500mV
I peak to peak 100mA

at base after the coupling capacitor:
V peak to peak 40uV
I peak to peak 8uA

at collector:
V peak to peak 300nV
I peak to peak 300nA

The values at collector is smaller than the base, i donno why

 

Maybe you can post the schematic?

 

Maybe you can post the schematic?

Here is the schematic please suggest.

 

I think you are misreading the results of the simulation. You are asking a lot with those 1 ohm resistors. Generally, you make the oscillator and then amplify the signal. Perhaps Multisim will let you use unusual component and values.

 

I think you are misreading the results of the simulation. You are asking a lot with those 1 ohm resistors. Generally, you make the oscillator and then amplify the signal. Perhaps Multisim will let you use unusual component and values.

I think there is no missreading, the readings are directly from the simulation probe.
The peak to peak values are still in uV even I increased the resistor values.

 

Look at the RMS values. I am not familiar with that simulator, but it looks like the p-p numbers are for ripple.

 

There is no real feedback there, I don't think it can work. You have one of the coils shorting the power supply, instant smoke. L1 should be going to the collector of the transistor and ground. You will need to dramatically increase the values of the resistors, 2 amps just for base bias (6V/2Ω)?

Colpitts...

Hartley...

They are more similar that you might first think. The concept is an inverting amplifier with a tank circuit that also inverts the signal. Work on the transistor amplifier a bit more first.

.

 

Here is a design I cobbled together. It has never been tested, but I suspect it will work first time. I am allowing the coils to conduct DC through to the transistor, turning what is a problem with your design into an asset with mine.

C2 is a power supply filter cap, and C3 will increase the gain of the transistor circuit. It might be eliminated with improved results.