Quote:
Originally Posted by Miguel Lopez
The coil L2 of Post#1 has a ferrite tube around the coil, and below the aluminium can. So, I guess its inductance should be relatively high.
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The coil L2 of Post#1 is tuned by 1300 pF. If the resonant frequency is 455 kHz, the inductance of the coil will be in the range 90 → 100 µH
Quote:
Originally Posted by Miguel Lopez
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The F.E.T. is N-channel. Making the gate +ve with respect to the source will increase the drain-source current. An excessive +ve voltage, gate-source, will produce an excessive drain-source current, probably damaging the FET. Since this F.E.T is N-channel, what is required is a range of d.c. voltages at the gate which go from slightly +ve to much more -ve, thus causing the drain-source current to vary accordingly. The diode is thus acting as a rectifier for the approx. sinewave occurring across the L/C tuned cct.
Al.