Compact Bridge Rectifier The bridge rectifier is an arrangement of four diodes connected in a bridge circuit. Its most common application is for conversion of alternating current (AC) input into direct current (DC) output. Since DCC is a square wave alternating current, most similar to AC waveform, the Bridge also converts DCC to DC output.
For any polarity of voltage input, the polarity going to the LED is always constant.
This circuit not only produces DC power when supplied with AC power, it also can provide "reverse polarity protection". That is, it will permit normal lighting of the LED when batteries are installed backwards, or DC power supply is reversed as when the rolling stock is traveling in reverse. The bridge keeps the LED lit and also acts to protect the LED it powers against damage that will eventually occur without this bridge circuit in place.
The size of a Bridge Rectifier is often roughly related to the peak voltage it is designed handle. Not in this case. This high quality super compact bridge rectifier you can see in the photo at left is rated for 200 Volts of power input! We use only the best tested and proven components in our LED assemblies.
Dropping Resistor An LED bulb can handle from 2 - 3.5 volts of DC power, depending on the color of the LED. White can handle more voltage than red, for example. If you were to connect an LED bulb straight to an 18 Volt power source without a resistor, you would see a very brief super bright flash and a puff of smoke as the LED burns out.
We have soldered a color-specific resistor to the LED so that it will work with common power sources without harming the LED. Our Universal LED's can run on anywhere from 7 to 19 Volts and are fully guaranteed to work, with a 2 year Replacement Guarantee.
The size of a resistor is often roughly related to the peak wattage it is designed handle and the ohms. Not in this case. The super compact metal film resistors we use (see photo at left) are rated for .5 watts of power input.
An LED draws .064 watts or less of power at top voltage.
Then your Universal LED light is double-shrink tubed and tested before shipping out to you!