brostenen wrote:

I have been thinking a bit about it the last couple of days, and I think that in order to get 3.6 volt, you need to build something with
resistors as "the cheapest" solution.

Nah... the resulting voltage would be dependent on the current draw. Use diodes (1N4001 for example) in series for a steady voltage drop.

One silicon diode drops the voltage by 0.7V, so if you're using 3 AA batteries: 4.5V - 0.7V = 3.8V -> I think you can get away with that.

Plus, this solution protects against polarity error AND recharging.

Any diode that drops with 0.9volt?

oerk wrote:

Nah... the resulting voltage would be dependent on the current draw. Use diodes (1N4001 for example) in series for a steady volt […]
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brostenen wrote:

I have been thinking a bit about it the last couple of days, and I think that in order to get 3.6 volt, you need to build something with
resistors as "the cheapest" solution.

Nah... the resulting voltage would be dependent on the current draw. Use diodes (1N4001 for example) in series for a steady voltage drop.

One silicon diode drops the voltage by 0.7V, so if you're using 3 AA batteries: 4.5V - 0.7V = 3.8V -> I think you can get away with that.

Plus, this solution protects against polarity error AND recharging.

The part you're looking for is a Zener diode. An integrated voltage regulator would also work, but I'm not sure if they're available for 3.6V.

Zeners are designed to breakdown and conduct at a specific design voltage. Therefore, the voltage across a Zener will be no higher than the Zener voltage.
http://ca.mouser.com/Semiconductors/Discrete- … ax1mh?P=1yuq69x
http://hyperphysics.phy-astr.gsu.edu/hbase/el … ic/zenereg.html

gdjacobs wrote:

The part you're looking for is a Zener diode. An integrated voltage regulator would also work, but I'm not sure if they're avail […]
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The part you're looking for is a Zener diode. An integrated voltage regulator would also work, but I'm not sure if they're available for 3.6V.

Zeners are designed to breakdown and conduct at a specific design voltage. Therefore, the voltage across a Zener will be no higher than the Zener voltage.
http://ca.mouser.com/Semiconductors/Discrete- … ax1mh?P=1yuq69x
http://hyperphysics.phy-astr.gsu.edu/hbase/el … ic/zenereg.html

Thanks... 😀 I will try and see, if there is any in dept video from EEVLOG on youtube.

gdjacobs wrote:

The part you're looking for is a Zener diode. An integrated voltage regulator would also work, but I'm not sure if they're avail […]
Show full quote

oerk wrote:

Nah... the resulting voltage would be dependent on the current draw. Use diodes (1N4001 for example) in series for a steady volt […]
Show full quote

brostenen wrote:

I have been thinking a bit about it the last couple of days, and I think that in order to get 3.6 volt, you need to build something with
resistors as "the cheapest" solution.

Nah... the resulting voltage would be dependent on the current draw. Use diodes (1N4001 for example) in series for a steady voltage drop.

One silicon diode drops the voltage by 0.7V, so if you're using 3 AA batteries: 4.5V - 0.7V = 3.8V -> I think you can get away with that.

Plus, this solution protects against polarity error AND recharging.

The part you're looking for is a Zener diode. An integrated voltage regulator would also work, but I'm not sure if they're available for 3.6V.

Zeners are designed to breakdown and conduct at a specific design voltage. Therefore, the voltage across a Zener will be no higher than the Zener voltage.
http://ca.mouser.com/Semiconductors/Discrete- … ax1mh?P=1yuq69x
http://hyperphysics.phy-astr.gsu.edu/hbase/el … ic/zenereg.html

Oh yeah, didn't think of that!

Diodes will work too, as every silicon diode drops the voltage by 0.7V. And no, there aren't any others. A few tenths of a volt too much won't hurt, though - your average AA battery will have significantly more than 1.5V when new, too.

I have been looking at some schematics.
Should that zener diode not be accompanied by a resistor of some sort?

Yes. The resistor is between the supply voltage and the positive Zener terminal. Size it according to the max current handling capability of the Zener:

Rz=(Vcc-Vz)/Izmax

also, the max resistor value should be Rz<=(Vcc-Vz)/Imaxload or the Zener won't regulate properly.

See the diagram on Hyperphysics which I linked to above.

I have done the final upgrades to this machine, in order to make it run for the last span of it's life.
Friends have donated the last missing pieces, that I needed, in order to make it work.
The VGA and the controller came from someone in Denmark and the soundcard came from Germany.
The HDD came from another friend in Denmark and I have used a new floppy from my stash.
I have installed a new BIOS battery, that I bought from eBay. Working like a charm now.

In order for the computer to see the harddrive, I needed to load a disk drive overlay.
And the OS on this machine are MS-Dos-6.22. If I change it, I will install 5.0
Hope people like the pictures of this machine. As I have used a lot of time to make it run again.

I will finish this off by shouting out a big thanks to everyone that has helped me getting this done.