Features 1、FOR BEGINNERS TO DIY: This product is a DIY BT33 dimming kit, unijunction transistor can control desk lamp, teaching part, suitable for beginners to DIY solder 2、SIMPLE PRINCIPLE: The working principle is simple, easy to understand, and also convenient to enhance the understanding of the working principle of single section transistors during the manufacturing and debugging process 3、REMARKABLE EFFECT: The dimming circuit can change the voltage across the lamp in the range of tens of volts to 200 volts, and the dimming effect is remarkable 4、COMPACT SIZE: Motherboard size for 45x30mm, easy to install, small size and lightweight, portable for you to carry 5、EASY TO INSTALL: Composed of unijunction transistor BT33 and unidirectional thyristor McR100-6, contain complete accessories and easy installation Specification Item Type: Dimmable Circuit Module Kit Motherboard Size: Approx. 45 x 30mm / 1.77 x 1.18in Package List 1 x Dimmable Circuit Module Kit