how to lower the ac voltage without using a transformer, because it's small.example of an ac voltage of 128 v to 110v,1500 watts of power used how?

 

Use a resistive voltage divider.

 

Use a resistive voltage divider.

At 1500 watts?

 

What is marked as 110V can easily vary quite a bit depending on the load on the system.
When working days and then nights it was not exceptional to see the voltage actually swing up into the 120's during different times of the day.
None of the test equipment was damaged by this.

 

I think it maybe would be better to use a non-polarized cap, but very careful when working with them. Just look up capacitor transformers.

 

This thread violates the forum's guidelines, and will be closed very shortly, if history is any guide.

 

So any discussions about a power supply are forbidden unless the supply has a transformer? So if someone wants to make a low-current 5V supply to run off a 9V battery, they have to figure out some way to use a transformer in it before they can ask questions? Or if a thread discussion lent itself to me describing how the very low noise 1000A programmable current supply I worked with at NIST works, that would be off-topic and forbidden because it doesn't have any transformers in it?

 

So any discussions about a power supply are forbidden unless the supply has a transformer? So if someone wants to make a low-current 5V supply to run off a 9V battery, they have to figure out some way to use a transformer in it before they can ask questions?

No, it only relates to mains-powered supplies. A moderator can answer any further questions.

 

And so he shall.

There is no way you can make a safe power supply without the isolation of a transformer. Trying to merely drop the voltage is a reciepe to injure or kill someone, as there are various senario's that could expose someone to the mains. A transformer offers true isolation, and is considered safe.

It is important enough that we specifically mention it in out Terms of Service (ToS):

6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:

• Any kind of over-unity devices and systems
• Automotive modifications
• Devices designed to electrocute or shock another person
• LEDs to mains
• Phone jammers
• Rail guns and high-energy projectile devices
• Transformer-less power supplies

We'll be willing to discuss alternate idea on a different thread.