Instructables
IMG_20121110_144553.jpg
IMG_20121110_144525.jpg
After discovering that my voltage divider based power supply didn't work very well, I set out to figure out how to make an better one. You are not really building anything but it is all done for you and you don't have to mess with any AC power (Very dangerous). But still, all power supplies have large capacitors in them that can hold ALOT of voltage. Just stick to my diagrams and you will be fine.
 
Remove these adsRemove these ads by Signing Up

Step 1: Parts

Old appliance (must have a AC input)
Such as.....
- DVD players
- Stereos (not sound bars)
- etc
Plugs
Wires
Electrical tape
Wire cutters
Wire strippers
Volt meter
Gloves (recomended in case wires short out) 

Step 2: Safety

Before we start, lets review a little bit of safety. First of all, always wear gloves when working with the exposed power board. When the supply is running there is AC power running through the many componets on the board. (their leads are exposed on the bottom which can give you a very very bad shock) Another is not to un-solder anything on the board, IT CAN CAUSE A FIRE OR WORSE. And pay attention to my instructions and diagrams.

Step 3: Take out the screws......

Open up your appliance and look inside. If you see the parts like the ones below and the line in, then you have found it. Unscrew the screws holding it in and take it out. Save the rest for later projects. NOTE: DO NOT TOUCH THE BOTTOM OF THE BOARD, IT CAN ELECTROCUTE YOU EVEN AFTER IT'S UNPLUGGED.
crich12 years ago
Huh? This Instructable doesn't really provide enough information for someone to successfuly complete the project. Not only that, if someone followed your instructions probably the next thing they would hear is a medic hovering over them saying "stay with me."
project_builder (author)  crich12 years ago
Thanks for the feedback, what kind of additional informatio should I add and to which part. And if you are saying that there is a danger of electrocution somewhere in this project please make sure to tell me, I used gloves to prevent that and had all stray wires attached to a ternimal block therefore keeping it from shorting out. Is that what you mean or is it something else?
Actually, there are lots of things you need to make this more clear, but I would start with pictures. What you are really talking about here is using the power supply portion of a used VCR, stereo, etc and kind of ignoring the rest of the circuit board. This does work, but we need to know a bit more, such as:

- How can we measure the output of the power supply to know what voltage it is before we decide whether or not to crack into it? Different devices use different voltages.

- Do we leave the components on the circuit board, or desolder them and use them to build an entirely new circuit? If building a new circuit, what parts do we need to use and how do we connect them together? (Remember, lots of pictures will help here)

- What does a basic power circuit look like? Maybe if I know this I can see how it is configured on my VCR board. Are there different kinds of power circuits?
(the answer to this is yes - something like the transformer circuit you are playing with here puts out a set voltage at a higher amperage ofthen between 1 and 5 amps depending on the size of the transformer, where more modern circuits do the same with lower amperages in the 700-1000 miliamp range. It depends on what you are running whether you need the higher amperages or not)

- How can I test this circuit to make sure it's going to do what I want before I plug it in? Or are we just smoke testing this thing and hoping we don't get smoke?

-Does this type of cirquit provide filtered power, or is it kind of "noisy" power? (The good news here is that modern electronics usually use banks of capacitors to provide filtered, less noisy power, which is great if I'm trying to power something with speakers.)

I could go on, but this is your Instructable. Beef it up a bit with some pictures and deeper explanation. I really do think this is a useful Instructable that people can really benefit from if you can polish it up. I'd also be happy to drop by and have a look at it anytime you like and provide more feedback if requested.

Oh, and to answer your question about the electric shock - the problem is you don't tell your user where to connect the leads to the circuit. If one just stars poking wires into a power supply hoping one of the connections just happens to work he or she will eventually choose the wrong combination and receive quite a jolt.
project_builder (author)  crich12 years ago
Thank you, I will revise this a little... I diddn't realise that I was missing THAT MUCH.