Tech Tear Down – Laptop Computer Charger

WARNING: DO NOT ATTEMPT TO DISASSEMBLE OR TAMPER WITH YOUR LAPTOP COMPUTER CHARGER; they contain giant capacitors which are capable of delivering fatal electric shocks if tampered with or touched. The charger used for this Tech Tear Down had not been plugged into a wall for over a year, and the capacitors were completely discharged.

Ever wonder what’s inside that little black box on your computer charger? Recieving yet more throw away electronics, I took apart an old computer charger to see what was inside.

Before I delve into what was inside, here’s a little background on what the little black box does. When you plug something into a wall, you’re plugging into your house voltage, which is usually around 120 volts, with alternating current (AC). That many volts is enough to fry most electronics, so there has to be a way to reduce the voltage and the current down to something more usable. That’s the job of the little black box on your laptop charger. It takes the 120 volts and steps it down to a much lower voltage, usually between 10-20 volts. You may notice a your charger getting hot if you have it plugged in for a while; that’s the extra voltage getting dissapated as heat.

It took quite a while to get it open, as it should, to keep the components inside from getting damaged or more importantly, touched. This first image is what it looked like with the black casing off. The printed circuit board and all of its components are encased in a few layers in metal and plastic to help dissapate the heat.

1_computer charger one piece metal shell

With the casing off, most of the guts were exposed. There’s great gobs of white glue, and a significant amount yellow plastic tape. In the middle you can see a capacitor (it has a smaller piece of yellow tape on it), or a component that holds and stores and electric charge. This would be just one of the caps (short for capacitor) responsible for zapping you should you open the charger up without discharging the unit first.

2_the guts with glue and tape laptop charger

Next I painstakingly removed all the tape and began to tear it apart to see all the components. It’s mainly made up of large capacitors and inductors (components that hold a current).

3_computer charger, labeled parts

I completely destroyed it, saving the ‘cool’ components. I got a nice 300Ω resistor (I didn’t have any of them), a giant 420 V 120 uF cap (good as a souvenir), some useless caps, and a decent small inductor I’ll try out on something. If you look at the tan PC board below, you can see that it’s well labeled as to where the components go, and every part has a name, like C1 or CX1.

4_computer charge, all the pieces together

Overall, it was interesting to take apart a computer charger. I saw some capacitor varieties I’ve never seen before.


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