24Vac LED power supply - flicker resolution

[Firelanterns]

Some help needed for a novice if anyone could please...!

I've purchased an outdoor LED lamp set - ships with a 24VAC 478Ma power supply - powers 20 "bulbs" each with 5 tiny LED's

As these are for outside, I've also purchased (from Maplin Electronics - UK - part code N69NC) a 24VAC 2A IP rated external power supply.

Obviously when I use this PSU - there is a "flicker" on the LED light string - I kind of forgot that there must be some form of additional conditioning electronics in the original PSU to give the LED's the DC (or appearance of DC!) they need.

The manufacturer refuses to help (safety I guess and all that!) - but could someone please recommend something i can put in circuit to stop the flicker ?

Many thanks in advance

DS

 

[MikeMl]

Here is a description of what you bought:

Description
A range of AC/AC transformers built into an IP66 rated enclosure Designed for powering garden & seasonal lighting, AC motors, or aquatic equipment that requires AC out voltages

For the LEDs not to flicker, the LEDs require that you feed them with 24VDC. Why didn't you just use the original power supply?

 

[MrAl]

Hi,

You could try a full wave bridge. If the current is only around 500ma you could easily use a 1 amp rated bridge rectifier. That will give you pulsating DC at 120Hz which is usually good enough. You could add some capacitors but you probably dont need them and adding caps is tricky as you might raise the average voltage too high.

 

[Diver300]

The flicker will be 100 Hz as the mains electricity in the UK is 50 Hz.

A bridge rectifier and a capacitor will reduce the flicker a lot. Even 100 μF will keep the LEDs from going out completely every 10 ms, and will make the flicker far less noticeable even if the current is varying a lot each cycle.