Hi All,

A mate just rang to see if I could shed any light on his question re
why don't the 'replacement' 'low voltage' (to use comparitive terms)
LED lamps work where a 'low voltage' (I assume 12V here) domestic
downlighter does (I don't know any type numbers atm).

I didn't know if these 'transformers' were just that in which case
they would be supplying the LED lamp with AC (so the LED might light
on the right half cycle all be it dimmer)? The LED assy could have a
bridge rectifier built in?

Or the transformers might be something more (electronic?) and not
'like' the different load applied by the LED lamp?

He has tested the LED lamps on 12V DC (battery) and they light up
fine?

Until he brings the various bits into work for me to have a look at
does anyone know what could be happening here please?

All the best ..

T i m

T i m wrote:
Hi All,

A mate just rang to see if I could shed any light on his question re
why don't the 'replacement' 'low voltage' (to use comparitive terms)
LED lamps work where a 'low voltage' (I assume 12V here) domestic
downlighter does (I don't know any type numbers atm).

I didn't know if these 'transformers' were just that in which case
they would be supplying the LED lamp with AC (so the LED might light
on the right half cycle all be it dimmer)? The LED assy could have a
bridge rectifier built in?

Or the transformers might be something more (electronic?) and not
'like' the different load applied by the LED lamp?

He has tested the LED lamps on 12V DC (battery) and they light up
fine?

Until he brings the various bits into work for me to have a look at
does anyone know what could be happening here please?

All the best ..

T i m

Some electronic transformers will not light up unless there is SOME load
on them. The LED may not be enough to do this.

T i m wrote:

He has tested the LED lamps on 12V DC (battery) and they light up
fine?

You may have just answered your own question, or alternatively, like
Dave said he has a SMPS rather than a real transformer and it is unable
to start due to lack of load.

--
Cheers,

John.

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On Thu, 01 Jun 2006 16:30:44 +0100, John Rumm
wrote:

T i m wrote:

He has tested the LED lamps on 12V DC (battery) and they light up
fine?

You may have just answered your own question, or alternatively, like
Dave said he has a SMPS rather than a real transformer and it is unable
to start due to lack of load.

Thanks both. ;-)

Apparently he can wire the two LED lights onto one 'transformer' so I
wonder if that would excert enough load?

If he let's me play with them I can measure the load current and check
that against the Txfmr spec ..

All the best ..

T i m