LCAP Free Energy

[Vortex1]

The electrolytic cap will have high leakage while the oxide layer is freshly being "formed", and this may account for some of the startup difficulty as greater leakage bias to the base occurs.

After "forming" the capacitor will have very low leakage resistance and the oscillator may be more difficult to start due to less base bias.

When there is not enough transistor bias, shock excitation can get the oscillator started by perturbing it into oscillation i.e. by just touching the base with a little stray static charge on your body.

In lieu of capacitor leakage, you could also add a high value (100k to 1 meg ) bias resistor to the + supply to get the base biased up into the slight conduction region, thermal noise should do the rest.

Blocking oscillators generally  start better when the transformer has a larger turns ratio such that high collector current is not required and the base current is obtained via a current step up from the turns ratio. This allows the transistor to operate as a high gain device by getting sufficient base current drive but not at the expense of high collector current, so it starts easier.

A 1:1 transformer such as a common mode choke used in a blocking oscillator circuit does not afford the necessary current transformation for effective base drive, but is not without some merit for certain special applications. It all depends on what you want to do.

[John.K1]

I have tried this thing and so far I can say : different LED, different results. Also funny thing is how sensitive it was to my hands or body.  When I moved my hands close to it I got impulses 2.9Vpp , when I moved my hands away ,impulses disappeared The impulses are almost good square waveform, but I have no light on my LED and I do not see any OU effect so far.  Also, my cap has to be shorted to get it running. I use different choke, it is standard bi-filar toroid. More to play with

[Vortex1]

I have tried this thing and so far I can say : different LED, different results. Also funny thing is how sensitive it was to my hands or body.  When I moved my hands close to it I got impulses 2.9Vpp , when I moved my hands away ,impulses disappeared The impulses are almost good square waveform, but I have no light on my LED and I do not see any OU effect so far.  Also, my cap has to be shorted to get it running. I use different choke, it is standard bi-filar toroid. More to play with

Sounds like your 2N2222 is running in the RF region.

[John.K1]

Sounds like your 2N2222 is running in the RF region.

Actually BC550 Radio frequencies are over 20KHz right?  Scope shows me just around 3KHz.

[Vortex1]

Actually BC550 Radio frequencies are over 20KHz right?  Scope shows me just around 3KHz.

The fT of the BC 550 is 300 MHz and an hfe of 800 typical. This is a formula ripe for parasitic oscillations. Note that 3kHz may be the major frequency but low level HF parasitics  can occur and cause the "Theremin like" effects especially when all of the stray capacitance and inductance is considered.. 

I don't doubt that there may be HF parasitics, but only a wide bandwidth scope will tell the truth.

Most experimenters scopes won't show the high frequency low level oscillations.