Darlington Oscillator (CB21142E)

Indicated by Popular Electronics, in an edition of the 90's, this circuit seems doubtful because of the inductance used, which must be large.

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Integrated AM Radio (CB20268E)
This circuit that uses potentiometer tuning, was found in a documentation from the 80's. The...
Ignition for cars with positive ground (CB23628E)
Another electronic ignition circuit for cars with positive ground. This circuit is from a Radio...
Biquad Filter MC4741 (CB14466E)
The MC4741 integrated circuit consists of four operational amplifiers similar to the 741 in a...