Electronic tester for quartz crystals

Using this circuit diagram can be designed a very simple electronic tester for quartz crystals. At this tester for quartz crystals a LED indicates if crystal tested oscillate or not .Tester was designed primarily to be used to test crystals with fundamental frequency between 1 MHz and 30 MHz.
Many crystals in the range 1-5-4 MHz oscillate easier when switch S1 is closed.

The typical current through the tester does not exceed 30 mA at a supply voltage of 9 V