Transformerless Power supply

[VaughnX5]

Hi first off I'm well aware of the risks. I'm in need of a transformerless power supply of about 5-25vdc - 500am - 1a or more. I don't have a transformer I can use. Instead I have a microwave HV Cap 2100VAC .90uf. I'm wondering if this can handle it.

Basing the idea off this circuit https://www.aaroncake.net/circuits/supply5.gif

 

[crutschow]

Hi first off I'm well aware of the risks. I'm in need of a transformerless power supply. I don't have a transformer I can use. Instead I have a microwave HV Cap 2100VAC .90uf. I'm wondering if this can handle it.

Handle what? You need more than a capacitor to build a power supply.

 

[VaughnX5]

I have recycled a few PC power supplies and monitor for parts. I power supply of about 12-24vdc around 3-5 amps or more.

Building off this circuit
https://www.aaroncake.net/circuits/supply5.gif

 

[Jackdaniel]

I have recycled a few PC power supplies and monitor for parts. I power supply of about 12-24vdc around 3-5 amps or more.

never!! U will't get 12v 5A Without a heavy transformer!

 

[VaughnX5]

never!! U will't get 12v 5A Without a heavy transformer!

Then what about 500ma or 1a, enough to power a 555 timer and a transistor.

 

[carbonzit]

Power supply for what? What voltage/current do you need? AC or DC?

Details, details. We can't read your mind. (Not yet, anyhow.)

 

[carmusic]

the power supply you show is dangerous since it is not isolated from main and is illegal in most uses unless you have a double insulated equipment

 

[Jackdaniel]

u willn't get one ampere without a transformer! The reason is the mains is nt isolated, maybe u will get around 350ma max. Why the hell r u taking risk?

 

[crutschow]

Using a capacitor to reduce mains voltage only works for a specific current for a given size capacitor. Also such a circuit is not isolated from the mains and is dangerous. Buy a 6V or 12V transformer for a few bucks and save yourself some grief.

 

[VaughnX5]

Please everyone I'm taking safety precautions.
I didn't come looking to be told to buy a transformer. Or to be told that what I'm doing is dangerous, its electricity when is it NOT dangerous. I know I'm dealing with main line. I know its not isolated. I know why I need a transformer and why its used. I've already built a power supply with a transformer. That's why I said I understand the risk at the beginning.

These are recycled parts, I don't care if I break the stuff that's kinda the point. I'm teaching myself electronics and I have no money at all to buy new parts.

So if we could please get past the warnings, I'd like to know more about transformerless circuits. this is for learning purposes. I'd like to build it so I know what its like first hand and how to regulate main both ways. I don't plan to keep it built long

If it helps I have a transformer from a microwave and 2 flyback transformers from 2 monitors, Air core and iron from PC PS. I have many caps of different sizes and different types, many VR / resistors from 1/8 to 1-2W, transistors NPN PNP, mosfets, BR, diodes and zeners, IC's like PWM controllers and quad comparator to 555 timer, I even have Multisim 11 to simulate stuff first. OH and big rubber gloves!

 

[carbonzit]

OK, but you haven't given us some crucial information (assuming that anyone here is willing to help you with this project):

What are you trying to power? In other words, what voltage and current do you want? Obviously, without that information, nobody can possibly help you (again, assuming they're willing to).

Having asked that, let me post a direct power-line operated circuit that I know for sure works:

**broken link removed**

Now, before I proceed, I must tell you that you're going to hear nothing but criticism of this. I know for sure that Eric Gibbs, one of the moderators here, hates this circuit, and will tell that if you build it, your house will burn down, your children will get electrocuted, and the police will come and confiscate it.

I'm here to tell you that it works. I have this very circuit on as I type. It's been merrily burning (metaphorically; no magic smoke has been released) for a few months now. I have no doubt that it will continue to do so for years.

Yeah, yeah: people here will tell you that it can't possibly work. Or that you need diodes to protect the LEDs (remember, a LED is a diode), or a resistor to discharge the capacitor, etc., etc.

I'm too lazy to check the capacitor value at the moment. I will tell you that it is a type (X2?) approved for power-line voltages.

It works. So what are you proposing to power directly from the power line?

Disclaimer:

I in no way suggest that this circuit is safe to build, or that it should be undertaken by anyone, whether experienced with electronics or not.
I make no claim that this is the best way to light LEDs (or anything else) directly from the power line.
I take no responsibility, legal or otherwise, for the consequences should anyone actually build this circuit.
I do not intend to use this circuit as part of any device produced for sale.
I only present and use this circuit for my own amusement.

 

[tvtech]

You really do not have a clue.

You do not know what you are doing. Stop and learn before you Electrocute yourself.

Listen or die. Your choice.

TV TECH.

Not directed @ carbonzit. Directed @ OP.

 

[ericgibbs]

Now, before I proceed, I must tell you that you're going to hear nothing but criticism of this. I know for sure that Eric Gibbs, one of the moderators here, hates this circuit, and will tell that if you build it, your house will burn down, your children will get electrocuted, and the police will come and confiscate it.

cz,
Please do not misquote me.!

I do not hate the circuit, I only caution users about its lack of isolation and its potential hazards.

IF you can find any of my posts where I have said these following words please feel free to post.
otherwise lets have less of your rhetoric and more facts.

and will tell that if you build it, your house will burn down, your children will get electrocuted, and the police will come and confiscate it

 

[VaughnX5]

OK, but you haven't given us some crucial information (assuming that anyone here is willing to help you with this project):

What are you trying to power? In other words, what voltage and current do you want? Obviously, without that information, nobody can possibly help you (again, assuming they're willing to).

Having asked that, let me post a direct power-line operated circuit that I know for sure works:

**broken link removed**

Now, before I proceed, I must tell you that you're going to hear nothing but criticism of this. I know for sure that Eric Gibbs, one of the moderators here, hates this circuit, and will tell that if you build it, your house will burn down, your children will get electrocuted, and the police will come and confiscate it.

I'm here to tell you that it works. I have this very circuit on as I type. It's been merrily burning (metaphorically; no magic smoke has been released) for a few months now. I have no doubt that it will continue to do so for years.

Yeah, yeah: people here will tell you that it can't possibly work. Or that you need diodes to protect the LEDs (remember, a LED is a diode), or a resistor to discharge the capacitor, etc., etc.

I'm too lazy to check the capacitor value at the moment. I will tell you that it is a type (X2?) approved for power-line voltages.

It works. So what are you proposing to power directly from the power line?

Thank you for taking the time to reply. ATM I don't want to power anything with it directly, mainly just getting the voltage and current down to DC small enough to measure with a multimeter and to get different V /A around 5-12vdc 500ma. Ideally I want a variable power supply for small experiments. I don't plan to use this type of circuit for that purpose though.

I just wanted to know if this HV 2100VAC .90uf can handle being C1 without issues.

 

[carbonzit]

Sorry, Eric; didn't mean to put words in your mouth. You never actually said "I hate that circuit!", nor claimed any of those things, but based on your previous criticisms, I just took that as a given.

It's called hyperbole (on my part).

 

[tvtech]

cz,
Please do not misquote me.!

I do not hate the circuit, I only caution users about its lack of isolation and its potential hazards.

My much promised design using an X2 cap as the "dropper" is almost good to go.....

Thing is, you need to have a safe and reliable housing to keep all safe. Insulation is critical for the user.

Electronics on test for a year now and reliable. The polycarbonate casing is still an issue.....

Cheers,
TV TECH

 

[carbonzit]

Thank you for taking the time to reply. ATM I don't want to power anything with it directly, mainly just getting the voltage and current down to DC small enough to measure with a multimeter and to get different V /A around 5-12vdc 500ma. Ideally I want a variable power supply for small experiments. I don't plan to use this type of circuit for that purpose though.

I just wanted to know if this HV 2100VAC .90uf can handle being C1 without issues.

I'm totally confused now: you want to measure the voltage and current with a multimeter, but don't want to actually use the circuit to power anything? Doesn't make sense.

Keep in mind that in order to measure current you need a load (some resistance), so as soon as you connect it you're powering something. (Voltage can be measured open-circuit without a load.)

Regarding the capacitor's fitness for this task: given the voltage rating of the capacitor, what do you think?

 

[ericgibbs]

My much promised design using an X2 cap as the "dropper" is almost good to go.....

Thing is, you need to have a safe and reliable housing to keep all safe. Insulation is critical for the user.

Electronics on test for a year now and reliable. The polycarbonate casing is still an issue.....

Cheers,
TV TECH

hi tvtech,
Almost all domestic PIR lighting systems use capacitors transformer-less PSU's, I have had 4, PIR's working for the past 10 years with no problems.

As you say, X2 rated caps and a secure enclosure are the main considerations.

I would not recommend using them for bench power supplies.

 

[tvtech]

hi tvtech,
Almost all domestic PIR lighting systems use capacitors transformer-less PSU's, I have had 4, PIR's working for the past 10 years with no problems.

As you say, X2 rated caps and a secure enclosure are the main considerations.

I would not recommend using them for bench power supplies.

Hi Eric

Little design that uses a PP3 E BLOCK rechargeable. Similar size to a normal light bulb here. Runs normal 5mm LEDS.
The next time you are in PE pay me a visit here down the road in KWT....I will show you all.

Kind Regards,
TV TECH

 

[carbonzit]

hi tvtech,
Almost all domestic PIR lighting systems use capacitors transformer-less PSU's, I have had 4, PIR's working for the past 10 years with no problems.

As you say, X2 rated caps and a secure enclosure are the main considerations.

I would not recommend using them for bench power supplies.

Amen to that last statement. (My emphasis added.)