Frequency Generation Without An Oscillator Ckt:multisim Simulation

[faltu]

hey guys,i was trying to get frequency without using any predefined oscillator ckt and i used an inductor.but now i m confused why i m getting any frequency as inductor acts as short circuit in dc source

 

[duke37]

To get a tuned oscillator you will need a tank circuit consisting of an inductor and capacitor. Various methods are used to tap into this circuit to provide power from the transistor and another tap is used to drive the transistor.
If the circuit shows an oscillation, it will be using the transistor capacitances to set the frequency.
Look up Hartley, Colpits and Clap.
Your circuit is presumably a simulation, 50A will soon let the smoke out of a BC547.

 

[Audioguru]

50A in a little BC547? Why doesn't Multisim read the maximum allowed ratings on the datasheet? it is 100mA (0.1A).

 

[faltu]

thanks duke37,
yaa is there any solution to the problem audioguru pointed out

 

[Harald Kapp]

is there any solution to the problem audioguru pointed out

Due diligence by the user of the simulator.

 

[Floly_lolye]

Just take a 555 and it works perfektly

 

[duke37]

Or find out how transistors are biased so that they pass sufficient current to do the job but not enough to damage them.

 

[LvW]

Remember the oscillation condition:
The loop gain (the gain around the complete feedback loop) must be unity - unity magnitude AND zero phase - for ONE SINGLE frequency only!.

 

[AnalogKid]

hey guys,i was trying to get frequency without using any predefined oscillator ckt and i used an inductor.but now i m confused why i m getting any frequency as inductor acts as short circuit in dc sourceView attachment 34028

By definition, a frequency is not DC. The function of any oscillator circuit is to turn DC into AC of some form.

ak

 

[faltu]

Or find out how transistors are biased so that they pass sufficient current to do the job but not enough to damage them.

yaa biasing helped

 

[faltu]

yes , i got the answer i was getting frequency due to the parasitic capacitance both in inductor and bjts as duke indicated