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How does thsi circuit work?

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rfanalogy

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It's a relaxation oscillator for sure but I don't seem to understand how L-C affects pulsing of LED?
Thanks.
 

It's a boost converter. The two transistors are arranged to increase gain (similar to a darlington or sziklai pair). The capacitor charge and discharges, causing voltage variations at the left-hand transistor. It creates hysteretic action turning the right hand transistor On and Off.

The joule thief is a cousin of this circuit. The joule thief has a coupled inductor, where this has several components which make up the biasing network.
 
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