DIY Diode Fan Controller - The Diobus

Part 1 - Some Info

This article will describe a very interesting computer fan controll solution. Here I will not describe in detail electronic schematics, because I hadn'n developed them myself. Rather I will describe how i made these controllers in my projects.

The original wchematics and descriptions can be found here:

(http://www.cpemma.co.uk/sdiodes.html)

If someone should try this guide I strongly advise him to read the above article thoroughly.

On this page I listed some of the information, needed to complete the controller.

In essence the idea behind this schematics is to present a cheap alternative to a fan controller. It will be utilize rotary switches and have light indication. There are some options for that, but I used light bars.

• Some of the controller's advantages:

• Rather cheap (more at the end of the article).

• Supports loads of about 1A without problem, compared to similar rheostats, which are big and expensive.

• Generated heat is little and distribute between all diodes. At full load of 1A it is about 1W per diode and with common fan is about 0.1W.

• Cau utilize the full 12 volts, as with common rheostats there is always dropdown and an extra switch has to be used.

• Contrary to rhesistors, the dropdown over diodes is almost the same for wide variety of currents, which means that under different load the exit voltage is almost constant. I.e. if you make the lowest voltage enough, there is no danger of fan's don't strting up.

• End finally, the addition of light indication is very easy and can be done in many different ways.

Here are some pictures of the controllers I made in my projects: