Will this replace a wal-wart? *PIC*

[aricaudio]

Provided Link: 12v 3 amp transformer


Hello, I'm checking this little guy out, and I've never wired up a tranny (even a small one ) before. Is this as simple as hooking up two mains wires to one side of the tranny (I'm assuming white & black wires??), and then solder to the tabs giving me 12 v.d.c.? I'm basically looking at this to replace a 3 amp wal-wart, with some careful soldering.

Thanks in advance, Aric

[Wolf]

> Hello, I'm checking this little guy out, and
> I've never wired up a tranny (even a small
> one ) before. Is this as simple as hooking
> up two mains wires to one side of the tranny
> (I'm assuming white & black wires??),
> and then solder to the tabs giving me 12
> v.d.c.? I'm basically looking at this to
> replace a 3 amp wal-wart, with some careful
> soldering.

3 parts to an AC/DC adapter:
1. Transformation- You need to change the mains voltage to the voltage you want in DC. Transformation accomplishes this. However, you need to be aware that after the 2nd step, it's higher than rated secondary voltage.

2. Rectification. Through a series/group of "one-way-valves" called diodes, the sinusoidal wave of AC is rectified to look like hills on top of the x-axis, and they are close together. The typical voltage off the rectifier stage = (secondary voltage * 1.4). In the mobile-environment, PWM(pulse-width-modulation) modulates the DC to simulate AC, then the litz-coil transforms to the correct voltage, rerectifies and goes to step three. You cannot transform a DC voltage to another voltage. You have to PWM first, or do it in the mains to secondary step.

3. Filtering/ripple reduction- Using a capacitor of the right size to shunt the rectifier's output, will store a charge, and minimize the valleys between hills in the DC curve, to give a flatter DC output scale. The "ripple" is how much the voltage droops between the hills. There are many ways to filter the DC to lessen ripple.

This is a simple explanation, so there is much not stated herein. Maybe you should read up on this before experimenting.
Later,
Wolf

[aricaudio]

> 3 parts to an AC/DC adapter:
> 1. Transformation- You need to change the
> mains voltage to the voltage you want in DC.
> Transformation accomplishes this. However,
> you need to be aware that after the 2nd
> step, it's higher than rated secondary
> voltage.

> 2. Rectification. Through a series/group of
> "one-way-valves" called diodes,
> the sinusoidal wave of AC is rectified to
> look like hills on top of the x-axis, and
> they are close together. The typical voltage
> off the rectifier stage = (secondary voltage
> * 1.4). In the mobile-environment,
> PWM(pulse-width-modulation) modulates the DC
> to simulate AC, then the litz-coil
> transforms to the correct voltage,
> rerectifies and goes to step three. You
> cannot transform a DC voltage to another
> voltage. You have to PWM first, or do it in
> the mains to secondary step.

> 3. Filtering/ripple reduction- Using a
> capacitor of the right size to shunt the
> rectifier's output, will store a charge, and
> minimize the valleys between hills in the DC
> curve, to give a flatter DC output scale.
> The "ripple" is how much the
> voltage droops between the hills. There are
> many ways to filter the DC to lessen ripple.

> This is a simple explanation, so there is
> much not stated herein. Maybe you should
> read up on this before experimenting.
> Later,
> Wolf

I was thinking it would be a "dirty" 12 volts ( non-regulated), but I did'nt realize there would be so much ripple in the wave. Thanks for the info Wolf- very well stated.

Bets regards, Aric

[envisionelec]

> 3 parts to an AC/DC adapter:
> 1. Transformation- You need to change the
> mains voltage to the voltage you want in DC.
> Transformation accomplishes this. However,
> you need to be aware that after the 2nd
> step, it's higher than rated secondary
> voltage.

> 2. Rectification. Through a series/group of
> "one-way-valves" called diodes,
> the sinusoidal wave of AC is rectified to
> look like hills on top of the x-axis, and
> they are close together. The typical voltage
> off the rectifier stage = (secondary voltage
> * 1.4). In the mobile-environment,
> PWM(pulse-width-modulation) modulates the DC
> to simulate AC, then the litz-coil
> transforms to the correct voltage,
> rerectifies and goes to step three. You
> cannot transform a DC voltage to another
> voltage. You have to PWM first, or do it in
> the mains to secondary step.

> 3. Filtering/ripple reduction- Using a
> capacitor of the right size to shunt the
> rectifier's output, will store a charge, and
> minimize the valleys between hills in the DC
> curve, to give a flatter DC output scale.
> The "ripple" is how much the
> voltage droops between the hills. There are
> many ways to filter the DC to lessen ripple.

> This is a simple explanation, so there is
> much not stated herein. Maybe you should
> read up on this before experimenting.
> Later,
> Wolf

Nice, Wolf! I like your description of the mobile environment power supply. Very good.

Interestingly, actual mobile power supply design has rarely been documented until recently on sites such as diyaudio.com and diymobileaudio.com. It was a nice little "black art" until this point. Fortunately, it's not a difficult technology to implement and it's made relatively easy for the DIY'er.

[Wolf]

> Nice, Wolf! I like your description of the
> mobile environment power supply. Very good.

Thanks!

> Interestingly, actual mobile power supply
> design has rarely been documented until
> recently on sites such as diyaudio.com and
> diymobileaudio.com. It was a nice little
> "black art" until this point.
> Fortunately, it's not a difficult technology
> to implement and it's made relatively easy
> for the DIY'er.

Interesting!
Later,
Wolf

[Wolf]

> I was thinking it would be a
> "dirty" 12 volts ( non-regulated),
> but I did'nt realize there would be so much
> ripple in the wave. Thanks for the info
> Wolf- very well stated.

> Bets regards, Aric

It would be 12VAC, not DC off the transformer.
Thanks, not a prob,
Wolf