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Enclosure for electronics projects (power supply)

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123mmm

Member
Hi, I am searching for a cheap and good enclosure for my electronics project. What I need in this moment is an enclosure with 350mm length, 200mm wide and 150mm height.
I have a few options:
1. To build this enclosure using wood - I have a few OSB wood plates at home, but I have only one hand saw to cut this wood, and I need screws and other things to fix the enclosure.
2. I can buy a plastic storage box, and I can make a front panel for this box, using FR-4 board or I can buy a small sheet of plywood for the front panel. The storage box is something like this: https://www.plasticboxshop.co.uk/bo...of-10-xl3-semi-open-fronted-storage-box-p1827 . This should be the cheapest option for my project.
3. I can buy a metallic box 35x25x15cm, but this is the most expensive option.

In the box, I will install:
1. One big heatsink of 16x17x5cm or two 20x10x2.5cm heatsinks.
2. A toroidal transformer, 120mm diameter.
3. Three PCB's, the biggest of them is 170x60mm.
On the front panel, I will install:
1. Two potentiometers.
2. One digital volt-ammeter.
3. Terminals for connecting the load.
4. On/Off switch.

1. What option should I choose ?
2. Are there any options ?
3. Where can I find a good second hand enclosure ?
 

gophert

Well-Known Member
Most Helpful Member
Your heat sink should only be "inside" the box if you have ventilation slots or a fan mounted to ventilate the box.
 

Reloadron

Well-Known Member
Most Helpful Member
Aside from a roll your own I like to use Bud Boxes for an off the shelf solution. Not knowing your location makes it difficult to suggest a vendor. Make sure you consider what gophert mentions as to heat removal.

Ron
 

gophert

Well-Known Member
Most Helpful Member
I would strongly suggest that you consider the need for a power supply before you start.
First, I am making some assumptions...

1) You are fairly new at electronics.
2) you want this to solve all of your power supply needs (0-30V) and ( up to 3 or 5 amps)
3) you are designing a linear power supply

If these statements are true, you must realize that using the power supply at low voltages and high current will require the power supply to dump the excess power as heat.

That is, if you design a 3 amp, 36 volt linear variable power supply, and need to use it for a 6v 2amp project, you'll need to dump 2 amps x (36v - 6v) = 2amps x 30 v = 60 watts of power as heat to get your 6 volts. That is a pretty big heat sink. Also, as temp changes, your output will likely drift considerably so accuracy will be difficult to control so you'll need an even bigger heat sink.

Note that my 1970's era HP power supply, 50v at 1 amp has a 4 pound aluminum heat sink.

I suggest a small, 1 or 1.5amp power supply. Ideally a switch-mode supply that you can adjust the output voltage. Before I go too far, please consider your goal.
 

123mmm

Member
gophert I am a almost new at electronics. I am building a linear power supply, 0-30V and 0-3A. I know that there will be high dissipation on the power transistors. I will include a 120mm fan on the heat sink. I already have a 170x160x60mm heatsink for TO247, but I am taking into account to use TO3 transistors, and some new heatsink(s).
 
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