BANDSWITCHED_GRID_DIP_METER

Published:2009/7/10 5:20:00 Author:May | From:SeekIC

For checking resonances,tuned circuits,antennas,etc.this circuit covers the 2-to 20-MHz range.Q1 serves as an oscillator tunable over this range vta C1 and bandswitched coils L1 through L8.When theprobe is coupled to a circuit resonant at the oscillation frequency,some RF power will be absorbed andtheoscillator output will drop,Q2,D2,D3,and Q3 form an RE detector and dc amplifier to drive meter M1,which will show the drop in Rf level,indicating resonance.R2 is a sensitivity control.



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