Why does my LC circuit not oscillate its energy between Electric & Magnetic fields?

[James2018]

Even with two 220 pF connected in series and a 470 uH inductor it still is no radio silence at 700 KHz.

 

[Baluncore]

Even with two 220 pF connected in series and a 470 uH inductor it still is no radio silence at 700 KHz.

Is there radio silence somewhere else in the band?
If not, slide the ferrite rod slowly out of the coil, listening for when the oscillator frequency moves up through the band.
Check the battery voltage, 5V; the base voltage, 2.5V; and the emitter voltage, 1.8V .

Why does nothing work for you?
Did you solder the wires or glue them?

 

[James2018]

Is there radio silence somewhere else in the band?
If not, slide the ferrite rod slowly out of the coil, listening for when the oscillator frequency moves up through the band.
Check the battery voltage, 5V; the base voltage, 2.5V; and the emitter voltage, 1.8V .

Why does nothing work for you?
Did you solder the wires or glue them?

We haven't taken the quality factor into consideration. Use this calculator to check quality factor, assuming effective capacitance is 110 pF and inductance is 470 uH: https://www.omnicalculator.com/physics/rlc-circuit
It is for RLC circuit, but for this Collpits oscillator I don't know what the effective resistance is.

And yet, I have to mention the previous Collpits oscillator did work, albeit emitting a disorted noisy radio waves because of the low resistances.

 

[Baluncore]

It is for RLC circuit, but for this Collpits oscillator I don't know what the effective resistance is.

Then measure the resistance of the coil with your multimeter.

And yet, I have to mention the previous Collpits oscillator did work, albeit emitting a disorted noisy radio waves because of the low resistances.

I don't believe it worked. The low value resistors stopped the oscillator by over-loading the battery.

 

[James2018]

Then measure the resistance of the coil with your multimeter.

I don't believe it worked. The low value resistors stopped the oscillator by over-loading the battery.

The resistance of my coil is 7. 2 Ohms. It gives a quality factor of 287.1 and a frequency of 700 KHz.

 

[Baluncore]

Is there radio silence somewhere else in the band?
If not, slide the ferrite rod slowly out of the coil, listening for when the oscillator frequency moves up through the band.
Check the battery voltage, 5V; the base voltage, 2.5V; and the emitter voltage, 1.8V .

What voltages did you measure?

 

[James2018]

What voltages did you measure?

Unlike a LED lighting up from this battery, this circuit doesn't even draw any voltage. It says 0 V near the battery. Certainly if this circuit works for other persons, maybe some components I used are flawed.

 

[Baluncore]

Unlike a LED lighting up from this battery, this circuit doesn't even draw any voltage. It says 0 V near the battery.

I think you mean it does not draw current, because it is open circuit.

So the battery is not flat, but the wires are not connected.
How do you join wires to components?
Test the connection resistance with your multimeter.

Your blurry photos show what looks like clear sticky tape being used to hold wires down. The static electricity from the tape, when it is unrolled, may destroy the transistor base junction.

 

[James2018]

I think you mean it does not draw current, because it is open circuit.

So the battery is not flat, but the wires are not connected.
How do you join wires to components?
Test the connection resistance with your multimeter.

Your blurry photos show what looks like clear sticky tape being used to hold wires down. The static electricity from the tape, when it is unrolled, may destroy the transistor base junction.

No, I have made the proper circuit by the original diagram and now it works. I have used those 2.2k, 4.7k, 10k and 560 Ohms resistances and it works. The only thing I did change was the tank circuit, with C5 and C2 replaced by 220 pF capacitors and the L1 replaced by the 470 uH inductor.

The antenna now has 10 mV of AC on average. No more 0 volts detection.

By the way, I tried other versions of the Collpits oscillator and they didn't work also, only this version did.

Thank you so much for your time and effort to try and help me.

 

[Baluncore]

Can you hear the oscillator as a silent frequency on the AM radio ?

 

[James2018]

Can you hear the oscillator as a silent frequency on the AM radio ?

Yes, at last! It's between 600 and 800, somewhere in between, see for yourself where the slider is:

 

[Baluncore]

LTspice simulation of your circuit shows that the 1 uF emitter capacitor, C3, seems to pull the frequency up, closer to 1 MHz than the expected 700 kHz.

If you move the AM radio further from the oscillator, you should get a more accurate frequency reading on the smaller signal.

 

[James2018]

LTspice simulation of your circuit shows that the 1 uF emitter capacitor, C3, seems to pull the frequency up, closer to 1 MHz than the expected 700 kHz.

If you move the AM radio further from the oscillator, you should get a more accurate frequency reading on the smaller signal.

If I place the AM radio 1 centimeter away from the inductor or from the antenna, the 700 KHz frequency goes completely silent. Otherwise, the noise reduces in intensity but not completely. The antenna does not have the right length to emit at a large distance. Half a meter away the noise reappears. It also silences 1400 KHz.