Large Scale Central

LED voltage in Annie

What is the LED voltage rating for the headlight and taillight on a 5th gen Annie? I am trying to determine if I can reuse the bulb when I install DCC or if I will have to swap it out.

I guess I might be asking the wrong question. What is the voltage of the lamp circuit? regulated 5v, 12v, straight from track power, etc…

For a LED that looks to be 20ma, I just hook up the CL2-N3, and not worry about supply voltage. This device is great at regulating current up to 90 volts.

I do use a current meter (60 year old VOM) in series with an unknown LED with a resistor on a varable DC supply to determine voltage and current draw.

On the current Bachmann Annies there has been a resistor in-line to the LED. It will take track voltage. Follow the wire coming from the LED and you can feel the resistor under the shrink tubing. I have not seen in these units a 5V regulator circuit. The new version coming out this spring is upgraded. Which is similar to the other spectrum locos with the plug N play socket.

Thank you. I will be installing a DCC decoder and track power is 23v on my system. I am assuming the resistor was spec’d for up to 18vdc. If so, I’m thinking the additional 5v might cause the resistor or be insufficient for the led. And doesn’t DCC need to be rectified to straight DC for LEDs?

Dan, you mention just hook up the CL2-N3. Looking at the data sheet the circuit shows a 100nF capacitor and diode. What size/type diode, is 1N4004 sufficient?

Do I have to deal with a heatsink?

I plan to use a Zimo MX696s decoder. Is the track voltage pin20 rectified to DC or straight pass through from the track? Does it matter with the CL2-N3 / TO-92?

If the center lug on the TO-92 says NC no connect, then why bother even having a third lug?

The Zimo decoders are marked V+ which is rectified track voltage which is track voltage minus the diode bridge drop. For DC operation you only need the CL2-N3. And if you add the super cap power storage, the lights will stay on for intermittent track power (dirty track/flaky turnouts).

Thank you very much. I plan to add the supercap flywheel. It sure makes a difference in running. Smooth, like buttah.