This simple circuit can be used to check the crystal element whether it is working or not working. Many circuit uses crystal as a important component to oscillate signals, these signal are main requirement for other device in the circuit, if the crystal got damaged means we can not easily test the crystal without any oscillator circuit, to avoid this situation here we given simple crystal tester circuit.
Circuit diagram for crystal tester
Construction and Working
In this circuit two BC547 transistors are connected together with capacitor c2 and this base terminals are works as a test terminal for crystal, the Q2 transistor drives LED1, if the LED glows then the crystal under test is working if the LED not glowing means the crystal might damaged or faulty one, this circuit can be powered by 9 volt battery.
why we are using capacitor c1,c2,c4 and resistor r1 in the crystal tester circuit
As a Oscillating Elements.