Crystal Test | Electronic Project Circuits

Posts Tagged ‘Crystal Test’

Simple Quartz Crystal Test with meter

In the circuit, above the BC548 is wired as a colpitts oscillator, the frequency tuned by insertion of a crystal. A good crystal will create high frequency oscillations, the output at the collector is rectified by the germanium OA91 diode and a deflection will appear on the meter. Thw more active the crystal, the higher the output deflection which may be adjusted with the preset.

Simple Crystal Test with LED Display

The circuit uses a working crystal again used to control the frequency of a colpitts oscillator. This time the output from the oscillator is taken from the emitter and is full wave rectified, the small dc bias will then directly cause the second BC548 to light the LED.

Read More Source: Andy Collinson
http://www.mitedu.freeserve.co.uk/Circuits/Testgear/crystal.htm
Thank you.