MOSFET_DIP_METER_

Published:2009/7/1 23:32:00 Author:May | From:SeekIC

Output of groundeddrain Colpitts oscillator using RCA N-channel dual-gate MOSFETQ1 is detected by CR1 and amplified by Q2 for driving meter. Frequency of oscillation depends on C1, C2, C3, and L1, and reaches 250 MHz when L1 is reduced to hairpin.Table gives values of plug-in assembly L1-C1-C2 for nine frequency ranges. Circuit was designed for 12-V supply but works well with 9-V battery shown if drain resistor RD, is shorted. Battery drain is about 20 mA. All coils are wound on Millen 45004 forms.-F. Bruin, A Dual-Gate MOSFET Dip Meter, QST, Jan. 1977, p 16-17.



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