Relaxation Oscillator Help

[Athosworld]

I made a 2n2222 oscilator (the super simple type)

it works with a speaker, but i tried to power a ferrite transformer with it and it seems it stops the oscillation. The transformer has 20t on primary and 310t on secondary, i wanted to use it as a fluorescent lamp instant starter.

I dont get any output on the secondary, ive tried a 1k resistor and a 2.2 uf capacitor. Is the frequency (around 2khz) the problem? Or is it the resistor?

 

[Papabravo]

I think you need more components to make a working oscillator.

 

[Tony Stewart]

super complicated photos with too many wires and bad connections with no schematic.

 

[Athosworld]

super complicated photos with too many wires and bad connections with no schematic.

(The cap is 2.2 uf and the LED is replaced with speaker)

 

[Athosworld]

I think you need more components to make a working oscillator

Why can it work with a speaker (wich is a coil) but not with transformer (also a coil)

 

[Tony Stewart]

Collector base leakage cause reverse Vbe to avalanche >>| -5V| causing relaxation discharges>~ -9V which overstresses the jcn. in the device but works... for a while. Does the transformer have the same impedance R+jX?

Apparently it's called the Esaki Effect but is not a reliable oscillator because the avalanche effect behaves as a cheap Tunnel diode with poor performance.

 

[danadak]

What is the battery V ?

Is this a product design or a one off hobby design ?

Do you want a reliable working circuit over T and V and device variation ?


Regards, Dana.

 

[Athosworld]

What is the battery V ?

Is this a product design or a one off hobby design ?

Do you want a reliable working circuit over T and V and device variation ?


Regards, Dana.

Its a hobby thing
I was first running it with a 12v wii power brick, now im running it with a 12v transformer and a half wave rectifier. I changed because the SMPS introduces noise to the circuit

 

[AnalogKid]

Power supply noise is completely irrelevant to this circuit. And, the half-wave-rectified line-frequency ripple voltage probably is greater than the switching supply output noise.

ak

 

[Athosworld]

Power supply noise is completely irrelevant to this circuit. And, the half-wave-rectified line-frequency ripple voltage probably is greater than the switching supply output noise.

ak

It is relevant, when you connect a speaker you can hear 60hz mains frequency superimposed with the high frequency tone the circuit makes. For some reason this is not the case with the 12v transformer.

 

[ZipZapOuch]

Measure the DC resistance of your transformer and your speaker. The transformer dc is likely so low and inductance so high and pulse-width of your oscillator so low and frequency so high that the signal you do generate is being filtered by the RL of the transformer primary.

Try flipping the transformer and connect your oscillator to the secondary and measure high voltage at the primary. Be careful, as you said, voltage will be higher than input

 

[Athosworld]

Measure the DC resistance of your transformer and your speaker. The transformer dc is likely so low and inductance so high and pulse-width of your oscillator so low and frequency so high that the signal you do generate is being filtered by the RL of the transformer primary.

Try flipping the transformer and connect your oscillator to the secondary and measure high voltage at the primary. Be careful, as you said, voltage will be higher than input

Speaker is 9 ohm
Transformer resistance is a short circuit

 

[Tony Stewart]

It's basically an RC tunneling relaxation effect so the R , L parameters of the speaker or transformer should have no effect with the current limited by R and a low transistor failure level. But the rep. rate is very much affect by the voltage above 9V threshold.

What was measured that you were not expecting?

 

[Athosworld]

It's basically an RC tunneling relaxation effect so the R , L parameters of the speaker or transformer should have no effect with the current limited by R and a low transistor failure level. But the rep. rate is very much affect by the voltage above 9V threshold.

What was measured that you were not expecting?

Little output on the secondary.

What kind of waveform is it supposed to produce? Isnt it something like this? (I currently have no oscilloscope)