power adapter

Hi. above is a charging cut-off circuit. As you can see in my demo. when voltage source is 5V, the load (R9) has 5W power. When voltage drops to 4V, the load (R9) has 0 W (cut off). However, my lithium ion charging pin for my battery is 4.26V. Thus, when battery fully charged at 4.2V, the...

Hello, I had an old AC adapter (230V AC to 14V DC). There was a small part where the insulation of the cable was damaged. You could see the copper coming through. So, I cut the damaged part away, soldered the wires back together, and insulated them with heat shrinks. However, when I then tested...