Working principle: When no light is irradiated onto the photoresistor, the triode is turned on, and the buzzer gets power and starts to chirp. When light is shining on the photoresistor, the triode is turned off, the buzzer is powered off, and the tweet is stopped. Here the triode is used as an electronic switch.

FAQ:

1,How about the quality of your product? 

   Before shipping out, all goods have been double verified by FUT quality inspection center ,Our test engineer will check for quality, including check the basic function of the hardware and software, the appearance, the packing, the necessary accessories and power adapter plug standard.  

  Less than 1% repairing rate within one year.    

2, What is the delivery time?
      Normally, 1-5 workdays after payment; 
      Special requirement orders, delivery time is negotiable.
      Rich stock can satisfy urgent requirement.And support small orders.  

3,What are the warranty and after-sale of the product?  
     If the products can't work after receiving it,we will replace your new product immediately and  make the judgement for the issue.
      If the products don't meet my demand after I received it,you can return back to us, we will refund your full payment.  
      1-2 years warranty according to different products 
      1-3 months to replace new items for free.     

4,Can you OEM|ODM? 
     Of course, we can. FUT have professional R & D Center,we can develop and manufacture according to customer's requirements.
      We can make your package please Such as printing your logo.  

5,Are you a manufacturer?  
    Yes, we manufacture different controller board, Exponsion Shiled Board, sensor Module for Arduino, 3Dprinter Controller Board,Raspberry Pi,Banana pi.
    Our factory and office are in Shenzhen, welcome you to visit at any time!