Need Advice - circuit board AC to dual DC output with resistors

Thread Starter

BbNnTt

Joined Dec 29, 2016
6
Hi All,
New to the website.
I need help finding or designing/making a circuit board that takes a 240v AC input (UK wall socket) and converts it into dual DC output at 3v and 9v. Not sure if such board exists or not. I am an complete idiot on all things electric so please keep your advice 'plain language'.
The purpose behind the circuit board sit inside a small case and to power a mini diorama model which has two sets of LED lights rated at 3v and 9v.
Thanks in advance
B
 

Tonyr1084

Joined Sep 24, 2015
6,896
If all you're lighting is LED's why not just use battery power? Much easier than trying to build a converter that will give you dual voltages. More portable and much less hazardous to your health - or the health of someone who might accidentally come in contact with your diorama.

In fact, LED's aren't so much dependent on voltage as they are dependent on current. The recommended current should be about 10 milli-amps. You can use a single 9 volt battery and light quite a few LED's.

Perhaps if you posted a picture of the LED's you wish to power, someone here can give you an even better solution. But yes, it can be done your way. But for someone with no experience, it's not so easy a task to explain, let alone for you to build.
 

Thread Starter

BbNnTt

Joined Dec 29, 2016
6
Thanks for your reply. That was quick :)
I initially planned for battery power - one dual AA with switch for the 3V street lights and one 9v battery with switch for the building lights. But the Diorama when displayed needs to have the lights on and in total I have 9 LED's. The package says set of 3 run at 35mA which doesn't last long on the batteries.
The Diorama has a wooden base which can safely store the electronics (to a limited size) and has a perspex case on top to protect the model.
 

crutschow

Joined Mar 14, 2008
30,133
If you really want to power it from the mains, then a couple of wall-wort supplies would likely be the simplest way to go.
Or one 9V wall-wort with a resistor to reduce the voltage for the 3V LEDs.
 

Tonyr1084

Joined Sep 24, 2015
6,896
I take it these street lamps and building lights are some sort of kit ? ? ?

There you go. Crutschow has a pretty good solution. I must have dozens of those things. But mine are made for US voltages (120 VAC)

Can you give us the specs for your lights ? ? ?
 
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Thread Starter

BbNnTt

Joined Dec 29, 2016
6
the 9v wall-wort is a good idea.
Is there anything needed to split the 9V into two circuits and add the resistor? Also which resistor would be needed?
 

Thread Starter

BbNnTt

Joined Dec 29, 2016
6
All the specs I have are in the links posted. The lights do not come with spec sheet or anything.

Using a resistor calculator I managed to get the following recommendation for the 3v lights. Do you think this is correct?
 

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Tonyr1084

Joined Sep 24, 2015
6,896
Little confused here. Where do you get your voltages from? From what I saw on the building light it is powered by 12 to 16 volts AC or DC. But I didn't see any kind of voltages on the street lamps. I'm wondering why they're not the same as the building lamps.

I also saw power supplies for the lights. Wouldn't it be easier to just buy one of those and plug your lamps into them? At least they're designed to work with your lights. Building something from scratch or bastardizing something to suit your purpose - unless you know what you're doing it's not going to be an easy task. You could EASILY burn out one or more, if not all of your lamps.

Is there anything on the packaging that tells you how many amps (milli amps) they draw?
 

djsfantasi

Joined Apr 11, 2010
8,396
Both the Faller Warm White LED Lights and the Woodland Scenics street lamps are meant to be powered from 16VAC, however... The street lamps are powered through a proprietary hub that includes circuitry for dimming each light individually for effect. If one were to purchase their Light Hub, which will light up to four devices - then the problem becomes just finding a 16VAC supply. It is likely that the street lamps could be powered otherwise, but Woodland Scenics does not publish the required information. They would have to be found through experimentation. The Light Hub can be found for $17USD.
 

Thread Starter

BbNnTt

Joined Dec 29, 2016
6
Have included as attachment what I have and know. The street lights can be purchased with controller and plug but due to the size of the Diorama and cost restrictions I opted to go without it.
 

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