12V LED - are they AC or DC or both?

[ExpatOilWorker]

Are all 12V LED light bulbs, with the MR16/GU5.3 sockets, dual AC-DC or are some specific AC and others strictly DC??

Online sites are notorious for faulty specifications so some are listed as AC, DC and AC-DC.

 

[ChristianBlessing]

If you supply the same voltage in DC as you would AC it will work, because LED lights require a DC power supply, which is built in. That same power supply can typically convert AC to DC.

 

 

 

 

 

[Crossy]

Yeah, the 220V ones are invariably AC although as noted they will usually work on the equivalent DC voltage.

 

The 12V ones I have are AC/DC so they work either way round on DC.

[sometimewoodworker]

3 minutes ago, ChristianBlessing said:

If you supply the same voltage in DC as you would AC it will work, because LED lights require a DC power supply, which is built in. That same power supply can typically convert AC to DC.

 

With all the LEDs I’ve used and installed they either have an AC supply incoming at 85~250v that goes through their own driver and outputs DC at the required voltage or a DC supply at the voltage required that has no driver and just feeds the LEDs directly.

 

it is vanishingly rare to be able to feed AC or DC to an LED driver. It is technically possible and there may even be some units that permit it, but the driver would be expensive as there is no demand.

[ExpatOilWorker]

1 hour ago, sometimewoodworker said:

With all the LEDs I’ve used and installed they either have an AC supply incoming at 85~250v that goes through their own driver and outputs DC at the required voltage or a DC supply at the voltage required that has no driver and just feeds the LEDs directly.

 

it is vanishingly rare to be able to feed AC or DC to an LED driver. It is technically possible and there may even be some units that permit it, but the driver would be expensive as there is no demand.

I have replaced many halogen lights with LED, just leaving the old halogen transformer, and always assumed LEDs also were DC.

My pool transformer however is 12 V AC, so just want to be sure I get the right bulb. 

 

The below is listed as AC, but it could be faulty specs. 

 

[ExpatOilWorker]

1 hour ago, Crossy said:

Yeah, the 220V ones are invariably AC although as noted they will usually work on the equivalent DC voltage.

 

The 12V ones I have are AC/DC so they work either way round on DC.

I also assumed they all are AC/DC Compatible, but some appear to be specific 12 V DC.

Rather confusing as they all share the same socket. 

 

[sometimewoodworker]

14 minutes ago, ExpatOilWorker said:

I have replaced many halogen lights with LED, just leaving the old halogen transformer, and always assumed LEDs also were DC.

My pool transformer however is 12 V AC, so just want to be sure I get the right bulb. 

 

The below is listed as AC, but it could be faulty specs. 

 

 

There are a very wide variety of LEDs, LED fittings, drivers and assembly variations possible.

 

directly mains fed, no driver used, LEDs or luminaires exist, as do virtually every variant of AC feed, driver required and DC feed, usually no driver needed though the voltage needed can be anywhere from about 1.2v up to 96v and higher.

 

having confused you the domestic LEDs are usually designed to replace another unit (your halogen replacement) plug into the 220~240v mains or a low voltage (12v or 24v) supply for cars trucks swimming pools.

 

It is not common to have a unit that is 12v DC or 230v AC supply as the driver is more complex/expensive.

you usually get bulbs that fit one supply system.

 

just to add even more confusion with the LED tubes they can feed one end line and the other neutral or a different design feeds line and neutral at a single end. Since the first version usually links the pins together you can get interesting bangs if fitted to the second type of fixture, magic smoke often escapes. DAMHIKT ???? 

 

TLDR buy the current (AC/DC) and voltage needed for your installation. The same connectors are used for both.

[sometimewoodworker]

39 minutes ago, ExpatOilWorker said:

I also assumed they all are AC/DC Compatible,

Possible but very unlikely IMHO. Your picture is for 12V only

 

this is for a single form factor BUT you must select either 12V or 230V bulbs with a GU10, MR16, or E27 base none are universal 

Edited November 8, 2021 by sometimewoodworker

[Crossy]

Important note :- I believe the units shown in the OP are NOT 220V/12V AC/DC universal!

 

They are either 220V OR 12V specified when ordering.

 

It's actually not that difficult to make a power supply that can be switched between 12V and 220V. It's less easy to make it auto-sensing and prevent it going fzzzt when connected to 220V when set for 12V.

 

I have some 12V photo switches which are actually identical internally to the 220V version except the 12V has a link, wheras the 220V has a capacitor in a particular position on the board.

 

[ExpatOilWorker]

2 hours ago, sometimewoodworker said:

Possible but very unlikely IMHO. Your picture is for 12V only

 

this is for a single form factor BUT you must select either 12V or 230V bulbs with a GU10, MR16, or E27 base none are universal 

The question is if 12V LED with the MR16/GU5.3 sockets are AC, DC or AC/DC compatible?

Nothing to do with 220V, they will of course all be AC.

 

[jackdd]

MR16/GU5.3 = 12v DC

MR16/GU10 = 220v AC

Anything other than that would be "strange".

 

The GU5.3 12v DC bulbs will probably run at 12v AC, but they will only be half as bright, and I don't know if it might damage them.

Edited November 8, 2021 by jackdd

[sometimewoodworker]

42 minutes ago, ExpatOilWorker said:

The question is if 12V LED with the MR16/GU5.3 sockets are AC, DC or AC/DC compatible?

Nothing to do with 220V, they will of course all be AC.

 

Basically any 12V or 24V LED for domestic use will always be DC as 12V or 24V AC is unobtanium in any normal domestic supply

 

Equally 220V will always be AC for similar reasons, not to mention that 220V DC will not allow you to unclamp your hand if you give it a shake. ???? 

 

off course nothing is technically stopping a 12V AC supply or a 220V DC one,  you will just never see either in the wild.

[Crossy]

4 minutes ago, sometimewoodworker said:

off course nothing is technically stopping a 12V AC supply

 

Actually a lot of the older halogen lighting power supplies were 12V AC at the lamp hence the LEDs being AC/DC.

 

Even the "DC only" LEDs tend to have a bridge rectifier as the front end so they work either way round.

[ExpatOilWorker]

37 minutes ago, sometimewoodworker said:

off course nothing is technically stopping a 12V AC supply or a 220V DC one,  you will just never see either in the wild.

Apparently most pool lights are 12 AC, so fairly common in that segment of the market. 

This is also new to me, hence the search.

 

Swimming pools and spa's always need 12 Volts of AC power. Most people hear 12 Volts and immediately think of DC which is used in cars and also outside landscape lighting. If you hook pool LED's to 12V DC, sometimes they work, but not correctly.

[ExpatOilWorker]

In conclusion, the vast majority of 12V MR16 light bulbs are dual AC/DC.

However others are dedicated AC and a few are only DC.

What a mess, especially when dealing with online platforms that more often than not only list part of the product information. 

[Crossy]

2 hours ago, ExpatOilWorker said:

In conclusion, the vast majority of 12V MR16 light bulbs are dual AC/DC.

However others are dedicated AC and a few are only DC.

What a mess, especially when dealing with online platforms that more often than not only list part of the product information. 

 

Yup, throw into the mix the fact that the same fitting can be 12V or 220V and you have recipe for the emission of lots of magic smoke.

 

It was bad enough in Korea where my place had a US style split supply. But a quirk of the wiring meant that some pendants were 115V and others were 230V. I just bought 230V lamps much to the annoyance of my Korean GF of the time. The 220V lamps in 115V fittings lasted forever. There was also a switch on a wire outside that turned off the local street light coz it shone in through the bedroom window