Elk M1 and Malibu Outdoor Low Voltage Lighting?

[Spanky]

I only had 4 lights and used a 1N5401 3 amp diode, but you can get 6 amp diodes and up also. Digikey 6 amp 100V diode.

As stated above, you are half wave rectifying the AC wave. You only get half the voltage to the lights, but it was enough in my case. The transformers tend to put too much voltage into the bulbs and burn them out in a short amount of time.

 

[gatchel]

Any rectifier diode rated for the proper amperage and voltage should work fine, Radio shack may even have something that might work depending on your amperage.

 

[WayneW]

I only had 4 lights and used a 1N5401 3 amp diode, but you can get 6 amp diodes and up also. Digikey 6 amp 100V diode.

As stated above, you are half wave rectifying the AC wave. You only get half the voltage to the lights, but it was enough in my case. The transformers tend to put too much voltage into the bulbs and burn them out in a short amount of time.

Doesn't the diode drop the current and power in half? The peak voltage would be the same, except for the typical .7 volt drop across the diode? I am looking for a cheap/easy dimmer and was hoping to use a diode to drop a 20W bulb down to an equivalent 10W.

 

[JeffVolp]

I had a problem with short life of the bulbs. They only lasted a few months. I placed a power diode in series with the line going out of the transformer and the bulbs never blew out again. It reduces the light slightly, but the bulbs last forever.

Our transformer has several taps inside to adjust the voltage, depending on load and wire length. I understand that when using halogen bulbs, the tungsten doesn't re-deposit properly if the voltage is not near the specified rating. You certainly don't want to over-voltage the bulb, but too low is not good either. Placing a diode in series will certainly increase the life because it reduces the power to almost 50%. It will reduce light output more than 50% due to the non-linear characteristics of the filament.

There are some new LED bulbs coming on the market. While expensive, they will save a significant amount of electricity over the life of the bulb.

We control ours with an in-line X10 module slipped into the 300W transformer case.

Jeff

 

[gregking]

I assumed most LV lights were DC. Are they really AC?

gk

I had a problem with short life of the bulbs. They only lasted a few months. I placed a power diode in series with the line going out of the transformer and the bulbs never blew out again. It reduces the light slightly, but the bulbs last forever.

I have problems with my 12 volt Malibu landscape lighting blowing out bulbs also. What power diode did you use? What's your theory behind using that?

Thanks! ;0

You are only allowing half of the AC sine wave to supply power to the lights. Essentially you are turning AC power into a very poorly rectified DC power.

 

[JeffVolp]

I assumed most LV lights were DC. Are they really AC?

It doesn't really matter to the bulb itself. However, the transformer produces AC. If you place a diode in series, it cuts off half the waveform. What is left is really only half the normal RMS voltage.

Jeff