CRYSTAL TESTER

Crystal is used as an oscillator, to generate a high frequency. In all the major electronic projects crystal is used instead of coil. Using this circuit you can analyse that your crystal working or not.The main components are

• BC550 Transistor 
  
• IN4007 Diodes
  
• LED
  
• Reistors(Values are specified)
• Capacitors(values are specified)
• Breadboard or PCB
  

CIRCUIT DIAGRAM

                 This electronic circuit consists of a crystal oscillator, two capacitors and a transistor forming a Colpits oscillator. A combination of diodes and capacitors are used for rectification and filtering respectively. Another NPN transistor is used as a switch to make the LED glow.

                The entire circuit is operated with two transistors, two diodes, and few passive components. If the testing crystal is good then it operates as an oscillator in combination with transistor. The diode rectifies the output of the oscillator and the capacitor filters the output. This output is now fed to the base of the transistor and the transistor starts conducting.

                 An LED is connected to the collector of the transistor through the resistor. The LED gets proper biasing and starts emitting light, i.e. it starts glowing. In case if any fault occurring in the testing crystal then the LED does not glow.