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Electrical Switch Relay For LED
Peter M asks readers:
I would like to run LED street lights off of my garden railway track. As LED’s only work in one direction can any one tell me what I need in the way of an electrical switch (relay) to enable the lights to work when I change direction?
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5 Responses to Electrical Switch Relay For LED
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Do you have just the one connection from the track to the street lights? You could wire a DPDT switch such that when you change direction you can throw the switch to keep the lights lit up. I am not sure about wiring the lights to the track though. It seems to me that your lights would be constantly dimming and brightening, and whenever you stopped to change direction they would go out. It will be more effort, but you might be better off in the long run to have a separate power supply for the lights.
You don’t say in your question whether you are running analogue DC or DCC. I have found that led’s will illuminate on ac but for only half the time, flicker is quite realistic, but you do need a suitable resistor in circuit to protect against surges. If running in DC a simple bridge rectifier across the supply with the output to the lighting should be adequate. Don’t forget the current limiting resistor as before
As commented above, connect the tracks to the AC input of the bridge rectifier. and the plus and minus output to the LED via a current limiting resistor. You can also add a SPST switch in the plus line to switch the LED’s on and Off. If the LED’s flicker a electrolytic capacitor can be added over the + / – wires to smooth the voltage.This way the polarity of the tracks do not matter as the diode bridge will sort it out.
If you use a bridge rectifier you can wire the LEDs to the + and – connection and wire the ~ to the track that way it it will always be in the right configuration for the LEDs just make sure the bridge rectifier has sufficient amperage for your layout.
As the comments above stated, you need to use a bridge rectifier between the track voltage and the LED’s. However, LED’s need to have the current regulated to around .015 amps, anything higher will damage them. You can find them at Newark Elctronics, here is the info: Invoice:
Line No: 1 Stock No:
Manufacturer Part No:
UOM:
Quantity: Price:
Extended Price:
60R6439
NSI50010YT1G
Tape and Reel Cut 1
120
$0.186
$22.32