Crystal detector circuit diagram

Published:2011/5/17 4:06:00 Author:Ecco | Keyword: Crystal, detector | From:SeekIC

When buying crystals, the detector can test the quality of the high-frequency crystal. Working principle is shown as the chart, it is a Kepizi high-frequency crystal oscillator composed of VTl and sJT crystal. When itis addedsJT crystal, it can provide positive feedback loop to the base of vTl, and VT1 starts oscillation, the weak signal from oscillation will be sent to vT2 emitter by coupling capacitor c4 and drive voltage doubler detector composed of C5, C6, VDl , vD2. Then the current amplifier VT3 turns on, the light-emitting diode VD3 is lit.Among them, the emitter vT2 can provide signals to voltage doubler detector, but also IV has the effect of isolation cushion, for reaching the start-up support of VT1. When it detects crystal, sometimes the brightness of VD3 is not enough, the conclusion is not sure, you can slightly adjust the operating point R3 of transistor vT1 to achieve stable oscillation, and then adjust the gain electrical equipment RP. It needs appropriate components. Generally you do not have to adjust. Power GB uses 6F22-nc9v to cascade batteries.



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