Alternate 3.3V source for Takky?

5 replies [Last post]
eeun's picture
Offline
Joined: Dec 19 2003
Posts: 1891

I was looking at an ipod battery hack in which a 5V zener diode is used to create 5V for USB-charging devices from a 9V battery.

What I'm wondering, and hoping those with more experience will know, is whether this could be adapted for Takky mods.

Quoting the 'meat' of the article form ipod hackaday;

Quote:

the zener diode conducts in the reverse direction when its breakdown voltage of 5.1 volts is reached, and the voltage across the diode will be that same 5.1 volts, so it acts to limit our 9 volt supply down to roughly 5 volts, which is what usb powers devices at.

the resistor (100 - 330 ohm) is there to keep the circuit from shorting when the load (your shuffle) is removed.  if you use a resistor less than 100 ohms you’ll know it because it will get hot.  if you use too large a resistor, you won’t be able to supply enough current to your device.

Could a 3V zener diode be used to supply the 'missing' 3.3V that's currently added to Takkys using an additional power supply or a tough to find (for some) regulator?

__________________

"Give a man a fire, he's warm for a day. Set a man on fire and he's warm for the rest of his life."
(Terry Pratchett)

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
moosemanmoo's picture
Offline
Joined: Aug 17 2004
Posts: 686
The strain on a CC's analogue

The strain on a CC's analogue board when it's not upgraded is already enough to cause some to fail, and using a stock analogue board with a stepdown component in a PowerPC system would cause a quick death. The additional power supply is essential, not only for 3.3v, but to offload some of the power strain.

__________________

Join the chat on irc.freenode.com, channel #applefritter.

eeun's picture
Offline
Joined: Dec 19 2003
Posts: 1891
That's not what I'm asking.

That's not what I'm asking.

Not all power supplies provide 3.3V, and I'd rather spend a couple dollars on a diode or regulator and use a PS I have on-hand, than buy a small PS soley for that 3V line.

There's several sites documenting the setup and use of the regulator, but for those who wish to take that path I'm interested in whether there's another option for obtaining the 3.3V.

__________________

"Give a man a fire, he's warm for a day. Set a man on fire and he's warm for the rest of his life."
(Terry Pratchett)

moosemanmoo's picture
Offline
Joined: Aug 17 2004
Posts: 686
Oh, I see what you're saying

Oh, I see what you're saying now. A 5v to 3.3v converter sounds fairly simple to make. As long as it doesn't have a risk of failing and frying 3.3v components with 5v, I can't see why it wouldn't work.

__________________

Join the chat on irc.freenode.com, channel #applefritter.

martakz's picture
Offline
Joined: Dec 20 2003
Posts: 634
Yup, that would be fine but I

Yup, that would be fine but I would not use the Zener. Get a 3.3V linear voltage regulator instead - alot more reliable.

__________________

Now using x86 machines. Bye bye iMac266 (Strawberry), G3 1400 and the G3 IIsi.

eeun's picture
Offline
Joined: Dec 19 2003
Posts: 1891
Re: Yup, that would be fine but I

martakz wrote:

Yup, that would be fine but I would not use the Zener. Get a 3.3V linear voltage regulator instead - alot more reliable.

That was the major reason for looking at the zener as an alternate: getting hold of a voltage regulator was difficult when I was building my Takky.

__________________

"Give a man a fire, he's warm for a day. Set a man on fire and he's warm for the rest of his life."
(Terry Pratchett)