Building a 24V AC and 0-30V DC Power Supply: Tips and References

[Bassalisk]

Hello people!

I've been absent from this forum for quite a while. But now I return with questions regarding a little project I have to do.

So basically I have to make a AC and DC power supply. I need 24 V AC output and 0-30 V DC power supply.

I have a transformer(I think its 220V/24V) which i plan on using to build such power supply

I have some circuits in mind, but I have no clue how to use 24V AC safely from transformer. So basically I would have to combine 2 different designs for DC and AC. I found some projects for 0-30 V variable but they don't cover AC supply.


Can anybody give me some references or schematics or pointers on how I can make such power supply?

Thanks

 

[Integral]

Just fuse the 24VAC. Get the fuse rating from the transformer specs.

You will have to jump through some hoops to get 30VDC from a 24VAC signal. It will not be as easy as just using a rectifier and regulators.

 

[Bassalisk]

Well i figure if 24V AC is a effective value and the amplitude of the sine wave I am rectifying is $24\cdot \sqrt{2}$ then that comes to about 33.94 V sine wave amplitude. If i rectify that I should get enough voltage for DC.

So a fuse will do a trick? Ok, I am gone shoppin!

 

[jim hardy]

You'll notice poor regulation at high DC output

but you should be able to get your 30 volts at not much current, maybe even 32 or 33
because the transformer is rated 24 volts at substantial current, probably makes 25 or 26 at zero current

reason regulation is bad is this:
With capacitor filter the current is delivered in big gulps near sinewave peak, so voltage drop along transformer's resistance is more than you'd expect. So peaks get 'flattened' as current goes up.

We learn best by doing and figuring out the complications that arise along the way ...

Experiment with a choke(inductive) input filter if you can - regulation will be better but voltage a bit lower...

old jim

 

[alphy]

for your question! Building a power supply can be a challenging but rewarding project. Here are some tips and references that may help you in your project:

1. Start by researching the basics of AC and DC power supplies. Understand the difference between the two and how they work.

2. Make sure you have a clear understanding of the transformer you plan to use. Identify the input voltage and output voltage, and make sure it is suitable for your project.

3. For the 24V AC output, you will need to rectify the AC voltage using diodes and capacitors. This will convert the AC voltage into a pulsating DC voltage.

4. To achieve the 0-30 V DC output, you can use a voltage regulator circuit such as a LM317 or LM338. These are adjustable voltage regulators that can provide a variable output voltage.

5. Consider using a dual power supply design, where one half of the circuit is dedicated to the AC output and the other half is dedicated to the DC output. This will ensure the safety of both circuits and prevent any interference between the AC and DC components.

6. It is important to use appropriate safety measures when working with high voltage. Make sure to use insulated tools and wear protective gear.

7. There are many online resources and forums where you can find schematics and tutorials for building power supplies. Make sure to double check any designs you find to ensure they are suitable for your project.

Overall, building a power supply requires careful planning and attention to detail. Make sure to research and understand the components and circuits you will be using, and take necessary safety precautions. Good luck with your project!