WeHonest DC lights, What AC Voltage?

You MOST CERTAINLY would need the resistor for 9VAC!  Without the resistor, with 9VAC with no resistor, the LED would enjoy a very short life on the order of seconds!

Thanks, I thought so.  So, if I wire it like this diagram below with a Diode in line with the resistor, I'm ok using 9 AC?

They sent resistors with the items I recently purchased.  I also added a diode to assure long life.

@hokie71 posted:

They sent resistors with the items I recently purchased.  I also added a diode to assure long life.

Yeah, I saw that they come with the Resistor, and I have the Diodes already (one recommended on another thread).  I was just checking to ensure with those both used on the same line as pictured above (diode not shown) could I use 9V AC or should I use a lower voltage?

By adding the resistor supplied for use with 9VDC and a blocking diode in the correct orientation (polarity shown below) you should be able to power the circuit with around 9VAC or so, if that's not enough, raise the voltage gradually until the LED turns on.

You're only running the led off half wave DC with just one diode.  That may also have an effect on brightness and perhaps lifespan.  I ran a 5v DC bus around the layout off an old slot car power supply to power items like that.

If I wanted to power these lights by DC, could I use an old Cell Phone charger that is 5V output and then cut the USB cord to connect to these lights?  I believe there are 4 small wires inside a USB cord, which ones do I use for the power?

I was thinking this might be an option but felt more complex that using the Diode and AC power.

I'd just plug it in and use a voltmeter to figure out which wires to use.  Pretty low current but it would work for a few less.  You can purchase a more robust two wire wall wart on Amazon in many different voltages pretty cheaply also, you might take a look.

@Dougklink posted:

You're only running the led off half wave DC with just one diode.  That may also have an effect on brightness and perhaps lifespan.  I ran a 5v DC bus around the layout off an old slot car power supply to power items like that.

There is no longevity issue running LEDs on pulsating DC, either half-wave or full wave if the voltage and current are kept to around the minimum required to turn on the semi-conducting junction.  In many consumer electronics, high-frequency pulsating DC with a lower duty cycle is how LEDs are often made to be brighter than they would on a smooth DC signal.

In the above diagram a somewhat higher AC input voltage would be required than 9V.

Even if using smooth DC (with or without the extra diode) a current limiting resistor should be used to prevent over driving the LED.  The ones provided with the "lights" would not work with 5VDC.

@Dougklink posted:

You're only running the led off half wave DC with just one diode.  That may also have an effect on brightness and perhaps lifespan.  I ran a 5v DC bus around the layout off an old slot car power supply to power items like that.

Half-wave power has no effect on LED lifespan.  Many LED's in commercial equipment that are driven using PWM.  LED's have a peak current rating and an average current rating.  Here's the absolute maximum ratings for an LED I use on my Chuff-Generator product as an example.

I also use PWM to drive the headlight LED for Rule-17 lighting with the Super-Chuffer.

@ArtsModelTrains posted:

If I wanted to power these lights by DC, could I use an old Cell Phone charger that is 5V output and then cut the USB cord to connect to these lights?  I believe there are 4 small wires inside a USB cord, which ones do I use for the power?

I was thinking this might be an option but felt more complex that using the Diode and AC power.

With any LED, you must have some sort of current limiting.  With a 5V source and colored LED's, a 150 ohm (or higher) value resistor will do the trick.

I guess I was thinking that half wave ac versus intentional pwm might be different due to the waveform but after reflection I think you are correct, won't matter.  Would affect brightness but not lifespan.

why not put in a full-wave rectifier bridge - they come in a variety of sizes, are cheap and can be installed essentially at the point of use?

I was working off of this thread from a while back when I purchased my WeHonest lights, using the Diode recommendation from here, pictured below.  Is a full-wave rectifier bridge better than the approach I was taking? I'm also not familiar with a full-wave rectifier bridge, do you have a recommendation on which one to get?

If you bought diodes, I bet you got a pack of 10, 20, 50 or in other words more than you know what to do with?  You can build your own bridge-rectifier using 4 of whatever diode you have.  Yes, purchasing a bridge-rectifier saves a bit on assembly time and such but considering the amount of component-level wiring/soldering/assembly you must do anyway, I'd suggest just rolling your own.  If this makes any sense, I can sketch out how to do this - it's fairly simple.

Also, what exact resistors did you get from WeHonest?  Part of the logistics problem is shipping costs will overwhelm the component cost for these kinds of parts.  I think minimum shipping in USPS for a 1 ounce package is something like $5.  Yeah, some people can sneak by putting a resistor in an letter envelope...

@stan2004 posted:

Yeah, some people can sneak by putting a resistor in an letter envelope...

Perfectly legal if it's less than 1/4" thick.   I do this a lot for a couple of components, many times I'm sending someone a component or two for free, no sense in paying four or five times the price for a padded envelope and the $3++ postage when I can do it for the price of a First Class stamp.  I cut a piece of cardboard and hollow out the middle.  The parts get sandwiched in with packing tape.

Yeah the lights I ordered say they come with a resistor but they don't provide much detail in the description.  Here is what the description said:

Specifications:

As for the Diodes, I ordered 10 (1N4003 (10 pcs) 1A 200V Rectifier Diode). I figured I had ordered 8 lights from WeHonest so 10 would be enough, but if I do build my own bridge rectifier I might need more.  I was thinking I'd power these off of one terminal block, could I use one Bridge Rectifier with that block or would each light need one?

@stan2004 posted:

If you bought diodes, I bet you got a pack of 10, 20, 50 or in other words more than you know what to do with?  You can build your own bridge-rectifier using 4 of whatever diode you have.  Yes, purchasing a bridge-rectifier saves a bit on assembly time and such but considering the amount of component-level wiring/soldering/assembly you must do anyway, I'd suggest just rolling your own.  If this makes any sense, I can sketch out how to do this - it's fairly simple.

Also, what exact resistors did you get from WeHonest?  Part of the logistics problem is shipping costs will overwhelm the component cost for these kinds of parts.  I think minimum shipping in USPS for a 1 ounce package is something like $5.  Yeah, some people can sneak by putting a resistor in an letter envelope...

FWIW, the item I bought came with 620 ohm resistors. Specifications are similar but not exactly the same- it might give you a benchmark on what to expect.

@ArtsModelTrains posted:

...

As for the Diodes, I ordered 10 (1N4003 (10 pcs) 1A 200V Rectifier Diode). I figured I had ordered 8 lights from WeHonest so 10 would be enough, but if I do build my own bridge rectifier I might need more.  I was thinking I'd power these off of one terminal block, could I use one Bridge Rectifier with that block or would each light need one?

One bridge-rectifier (4 "loose" diodes) can power dozens of lights. 

I figure all 10 of your signal are not controlled by one toggle switch.  Not to worry!  As shown above 1 bridge-rectifier (or 4 loose diodes configured as shown with the silver bands) can power multiple toggle switches.  Each toggle switch might be controlling one or just a few of your signals. 

Each signal though MUST have its own resistor.

@gunrunnerjohn posted:

Perfectly legal if it's less than 1/4" thick.   I do this a lot for a couple of components, many times I'm sending someone a component or two for free, no sense in paying four or five times the price for a padded envelope and the $3++ postage when I can do it for the price of a First Class stamp.  I cut a piece of cardboard and hollow out the middle.  The parts get sandwiched in with packing tape.

I think it's a your-mileage-may vary.  Perhaps you're just a lucky guy!  I've received small items (less than 1/4" thick) crushed, pulverized, distorted, missing (ejected from envelope) etc. when sent in a plain envelope with a first-class forever stamp (now 58 cents).  If you've ever watched a video (youtube if you're really interested) of the high-speed USPS sorting machines whipping envelope around bends and turns you'd know where I'm going.

That is, IMO if you do hollow-out a piece of rigid/stiff cardboard to mail a few penny resistors, diodes, or whatever, you should designate the envelope nonmachinable.  I write "NONMACHINABLE" on the envelope and pay the nonmachinable surcharge which is 30 cents (it just went up at beginning of year).  So the postage for a 1 oz envelope would be 58 cents plus the 30 cent surcharge or 88 cents.  Or if you buy or have bought the "forever" nonmachinable so-called butterfly stamp then you're good to go.  In theory (and I repeat, in theory) USPS should not run a nonmachinable designated envelope thru the machinery - instead manually sorting and hence the surcharge.  As to whether they really do this or not I will never know...but this is how I would send such items.

Just saying...

Interesting, I just found the thing that said a first class letter couldn't be more than 1/4" thick and left it at that.  So far, most of the stuff I've sent has made it.

Learn something every day...