beepjuice;
Do NOT connect these lampposts, or any other LED, to the "accessories" terminals of a power pack. Typically the accessories terminals output AC (Alternating Current) which can destroy the LEDs. Unlike incandescent lamps, the coils of twin-coil switch machines, and a host of other electrical devices, LEDs (Light Emitting Diodes) do not run on either AC or DC. They are designed to run on DC only. The resistors included are intended to limit the amount of current that passes through the LEDs. That amount of current is affected by the amount of DC voltage applied to the LED and resistor. The "DC/track" output terminals of a power pack may have up to 12-18 volts of DC on them , when the speed control is turned all the way up. That may be too much for your LED and resistor, so turn the speed control all the way down to zero before doing the following test.
To test things, I suggest you try another LED, rather than risking one of your lampposts. Connect that "test" LED, and a resistor of the same resistance as the one on a lamppost, to the "DC" or "Track" terminals of your power pack. Then turn the knob up to about one quarter power. The LED will either light, or not, depending on which way it's attached to the terminals. If it didn't light then turn the speed knob back down to zero, and reverse the wires feeding the LED/resistor combination. In other words, put whatever wire was on terminal 1 onto terminal 2 and vice/versa. Try turning the knob back up to one quarter power. The LED should now light.
To do this, and many other electrical jobs on your railroad, properly, and easily, you really should use a multimeter. If you don't have one, then you can get one from Harbor Freight
www.harborfreight.com for only $5. (see photo)
It's a basic meter, but it does everything you'll need to do on the railroad, and it comes with directions.
Two of the things you will be able to use your new meter for right away, are to measure the resistance of one of the lamppost resistors, in order to match your "test resistor" to it, and to measure the minimum DC voltage coming from the power pack's DC terminals, that will light your LED. You can increase the voltage SLIGHTLY to make the LED glow brighter, but too much voltage may burn it out.
{Technical stuff} .........Resistors are also marked with color bands to indicate their resistance value in electrical units called "Ohms."
So, if you get a test resistor that has exactly the same color bands, in the same order, as the lamppost resistors, then it should be the same resistance that they are.
The colors work like this to show the number of Ohms of resistance a particular resistor has;
black = 0, brown = 1, red = 2, orange = 3, yellow = 4, green = 5, blue = 6, violet = 7, gray = 8, & white = 9.
Reading left-to-right from the end of the resistor with the most space between the color band, and the end of the resistor, the first two colors are normal numbers. For example, violet gray would mean 68 The third band indicates the number of zeros that follow those first two numbers. For example, violet blue black would mean 68 with no zeros, or sixty-eight Ohms. (By the way, 68 Ohms is a good resistance to operate an LED on 12 volts DC) However, violet blue orange would mean 68 followed by 000, or sixty-eight thousand Ohms! With that much resistance, the LED would not light at all. Resistors have a forth band that will be gold, silver, or blank. Some even have a fifth band. You can ignore the fourth and fifth bands. They just indicate the % of accuracy of the stated value, and for your purposes, that doesn't matter at all.
Now do you see why it's easier to just measure the resistance with a meter?
Good luck & Have fun;
Traction Fan 😊
