LM358 IC Chip A heart-shaped breathing lamp circuit composed of LM358 chips. The light gradually changes from bright to dark, then from dark to bright, and it feels like a person is breathing. Learn to Solder This soldering DIY kit can help you learn basic electronic knowledge , circuit principles and practice soldering skills, allowing you and your children, students or DIYers to learn soldering skills happily. Great Gift It’s not only a PCB board for practicing welding, but also a creative gift for your kids or grilfriend. Helps your child to learn about the soldering project knowledge and skill. Tools Required Electric iron 30W Solder wire 0.8mm Multimeter Tweezers Diagonal pliers Read more Matters Needing Attention: 1. Power supply voltage: 5V (DC power supply) 2. Board size: 58 * 50mm 3. Check and identify the quantity and specification of components according to the list of components. 4. Use a multimeter to check and confirm all resistance values. 5. Confirm the polarity of the components and the installation direction on the circuit board in advance. 6. Please download the user guide on the detail page before use, which will guide you how to finish step by step, perfect for school basic electronics experiment projects. Read more Install the power switch: Pay attention to the direction of the notch at the bottom of the switch corresponding to the mouth shaped silk screen on the circuit board. Installation of integrated circuit: Pay attention to the gap of integrated circuit corresponding to the gap of circuit board screen printing. Installation of LED: Pay attention to the difference between positive and negative poles of LED (the long foot is the square pad of the circuit board corresponding to the positive pole Install the optional power cord or battery box: Weld the red wire to +. The black wire is welded in the following figure. Read more