12v LED RV Bulb Polarity? (E26 Standard Base)

[XERTYX]

I'm going to be installing my 12v light bulbs with a standard 120v base and I'm wondering does anyone know if the center pin is positive and the screw thread is negative or vice versa?

I have one off site wired into a small bank already but its connected using the old reliable 2.1mm barrel jack connector like you plug into a "solar generator" and I forget the polarity as I wired it years ago.

I'm not seeing anything online so I'd appreciate it if someone knows. Thanks.

 

[bullfrog]

It has been a long time since I used a 12 volt DC bulb like that but my guess is the center pin is + 12 volts and the threads are - 12 volts. I would try some jumper leads from a 12 volt battery to the 12 volt DC bulb to be sure. The bulbs I used were filament bulbs not LED.

 

[highdesertranger]

120volt does not have a positive or negative. They have hot and neutral. Wire it however you want I am assuming your using 12v LED's I didn't even realize they made 12v ones that fit a 120v base. That doesn't seem right to me. Highdesertranger

 

[XERTYX]

Yeah it's a standard replacement for the old school filament 12v RV light bulbs. Same E26 screw thread base. The box specifically says 12v AC DC NOT FOR 120V AC. Haha. Almost makes me wanna see what it would do if I did.

https://www.amazon.com/gp/aw/d/B075XZ3CTL

I'm gonna try jumpering it if all fails. I'm pretty sure that's what I did last time.

Edit:
This is what the one I used before is plugged into. I would just go check it but its installed on my family's property about 30 miles away.

https://www.amazon.com/Volt-Light-Bulb-Socket-Wire/dp/B0768QFN27

 

[highdesertranger]

wow there you go. I would guess that the center is positive, mind you this is only a guess. they made incandescent that used that base but they don't matter how you hook them up. Highdesertranger

 

[XERTYX]

Yeah that's what I'm thinking. But yeah you CAN still find the 12v incandescent ones but I think even wally world near here closed those out. The LEDs just replace em. 7 watts. When I first got my last one I ran it off of a USB buck converter. I had a USB bank with about 74 wh of capacity and it would run it for ~10 hours.

I'd rather not chance it testing for polarity but I'm fairly certain they have a rectifier circuit in them as they're 12v AC/DC so if I reverse it it just wont turn on I'd imagine. Just hoping someone might know.

FYI these little buggers throw off a ton of light. As much as a household 120v LED 60w replacement bulb.

 

[Tom_M]

An LED is a rectifier (Light Emitting Diode) so if you hook it up backwards nothing will happen. Some LED bulbs have circuitry built in to handle a broad voltage range. These typically will function with either polarity.

 

[XERTYX]

In case anyone is wondering attaching 12v + to the center pin lights these bulbs. I didnt try it another way. I imagine as they're 12V AC/DC that they have a diode to rectify the AC and energize a capacitor before the LED bulb to eliminate flicker.


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Such as.        --->|----|C------>|------

 

[Sofisintown]

120volt does not have a positive or negative.  They have hot and neutral.  Wire it however you want I am assuming your using 12v LED's I didn't even realize they made 12v ones that fit a 120v base.  That doesn't seem right to me.  Highdesertranger

Yes, they do make them and I got me a 4 pack. To figure where is + and - , I used a 9 volt battery touching the base. The bottom of the base of these bulbs is positive and the sides negative.

OP: You can use a 9 V battery to check which wire is the +of the wiring.

 

[Tom_M]

In case anyone is wondering attaching 12v + to the center pin lights these bulbs. I didnt try it another way. I imagine as they're 12V AC/DC that they have a diode to rectify the AC and energize a capacitor before the LED bulb to eliminate flicker.
                                                  ➚
Such as.        --->|----|C------>|------

As I stated earlier, an LED is a diode. No additional diodes are required and it will work on AC or DC. The simplest circuit would be an LED and a series resistor. The AC power source is 60hz and the human eye will not notice any flicker. Any bulb purchased would already have circuitry built in, either a resistor or regulator circuitry.