wiring leds to ac do i use a transformer

I'm working on converting an old record player into a clock and adding some LEDs. I know its a bit of a stretch to ask for help with something like this on this forum, but everyone here is really helpful, plus I'll be using 12v power. I've done this once before, but the record player I used before was in better condition than the one I have now. This was my end result: ALSO! If you know how to make the hands of the clock light up I'd love to hear it! So moving on, on this second record player, I used a DMM on various locations to try and find a good power source for the LEDs. However, the highest voltage I can find is about 2.6, which I don't think is enough. Also, nothing will work on the record player: the turn table won't turn and the motorized arm doesn't work. Unlike my previous project, my plan this time is to bypass the existing wiring and put in my own. And this is where I need some help. I don't want to mess with batteries to power the LEDs. I'd like to be able to plug this thing into the wall, flip a switch, and have the LEDs turn on. So if I'm understanding things correctly, I'll need a transformer to make this happen? I'm thinking it would go like this: power cord to transformer, then transformer to LEDs/resistors. Is that right? I keep reading about transformers and wattage and then I get more confused. This is the transformer I'm thinking of getting. This is the switch I'm thinking of getting. These are the LEDs I already have. I plan on using 24 of them for this project. These are the resistors I already have. I used the calculator on led.linear1.org to get this and plan on wiring the LEDs this way: I basically don't know for sure if I can wire the LEDs safely this way. Can a very wise member with vast knowledge and great experience help me out on this please? Now that I've explained my plan, here are my questions: 1. Will that transformer work for this project? If not, why? And which transformer would you suggest if it won't work? 2. Will that dimming switch work for this project? If not, why? And which dimming switch would you suggest if it won't work? 3. Am I totally off base and need to do more research before annoyingly asking questions? 4. Anything else you want to tell me such as suggestions or tips? 5. If you have any other cool ideas that I could do with the lights please let me know.

Yes, a transformer will work. But first I suggest checking what motor you will be using and its power & voltage requirements. (I assume no other power is needed for pre-amps etc.) Unless it is a 120VAC motor you'll need a transformer (or a more modern SMPS supply) and hence you may be able to use that for your LED power source. For LEDs I suggest a filtered DC supply (hence a transformer with bridge rectifier and a cap, or SMPS DC supply). That might be obtainable from the motor's power supply. The LEDs consume 24 x 20mA x 2.1V = 24 x 0.042mW = 1.008W or about 1W (as per your calculator) which is probably negligible compared to the motor. The resistors and dimmer add a bit extra, but I doubt the total load would be as much as 2W. But the resistors depend on the supply's DC voltage and the number of LEDs per string. EG - if it's a 24VDC supply you could have 3 strings of 8 LEDs. Re the dimmer, do you actually want to be able to vary the brightness, or merely be able to adjust for an optimum brightness or maybe change between 2 or a few different brightnesses? The max LED brightness can be varied by the resistor value (and maybe experimentation). From there it may be a simple case of adding an extra resistor for another brightness rather than going to the complication of adding that LED dimmer (which may add noise which is picked up by the needle/cartridge etc). A variable current limiter may be another means of dimming without noise problems - eg, an LM317T 3-terminal voltage regulator and variable resistor or selectable fixed resistors. But IMO, start with the what the motor (or other things) need to supply its (or their) power.    As to other cool things, anything is possible... LED chasers, signal modulated brightness, etc. But decide that before obtaining any dimmer. (Such circuits will involve chips or uPCs etc and they will have to control the dimming.)

Thanks for the detailed response oldspark. I will not be using this to play any records so I don't need to worry about any noise being picked up by the needle or powering the motor. Even if I wanted to play a record I couldn't. Sorry for the confusion. I'm just using this as a "shell" for a unique looking clock. The only thing that is going to require power are the LEDs. The clock's quartz movement will remain untouched and run off of a battery. I just re-read the description for the transformer I picked out and (I'm not sure how I missed it) it doesn't work with LEDs anyway. Sorry, I'm not sure I completely understand the bridge and cap. Could I use a transformer like this and add on a bridge like this? When you say cap, do you mean capacitor? If yes, would this one work? Where would I wire the capacitor in with the transformer? I plan of having four strings of six LEDs and one 1/4W resistor for each string. So if the dimming switch adds a bit extra but the total is still under 2W, does the transformer I picked out in the paragraph above still work? Yes, I would like to be able to change the brightness of the LEDs. I'd like to have full dimming capability. I wouldn't mind being limited to a few brightnesses, but it seems like both full dimming and a few brightnesses would be equally easy. I would just use the LM317T 3-terminal voltage regulator you suggested as well as variable or fixed resistors. Is that correct? As for the cooler things, now that I think about it, I'll just stick with dimming as its probably cheaper and much easier. Thank you for your help!

I'm such an idiot. Typical me - I looked at the LEDs and not the hands! I'm inclined to stick to your initial design/suggestion. Initially I had concerns about that 12V 10-60W-120V Dimmable Transformer but I reckon it's fine - and I hope I'm not wrong... POST EDIT - I reckon it's NOT fine, but see later... But the logic of my insanity is... It's an "electronic transformer" which in my jargon means it's not a transformer at all, but an SMPS (switched mode power supply). [ LOL - gotta love the term "plugpack" - they can be transformers or SMPS. ] It's dimmable because it either tolerates typical AC phase-control dimmers or it has a control terminal/wire that coverts some dimming signal (eg, a voltage input of 0-5V or 1-5V etc) which varies its output voltage. Its "not suitable for LEDs" because LEDs are not dimmed by voltage like halogens and other lights can. Proportional dimming of LEDs is by current - eg, PWM (else analog current limiters). /end of the insane logic part. An issue with the dimmable "transformer" is its output is AC just like a real transformer, and you want DC, both for the LEDs & the dimmer. [FYI - LEDs will run on AC but there are lifespan issues etc.] Also that its 10-60W rating suggests a MINIMUM 10W load. But an AC output requires "DC power supply" design. The main "trap" is that a 12VAC transformer does NOT produce 12VDC. The resultant DC output depends on the design. And now I'm thinking why not use a plugpack? That overcomes all my concerns for AC safety and whatever regulations you have. Another advantage - switch LEDs on/off at wall socket; no switch on the clock/player, and no need to worry about powered but unused plugpacks. Disadvantage - switch LEDs on/off at the wall socket; no local switch on the clock/player. Ah - place the plugpack in the clock... One big advantage you have is the negligible power. Even if it's 5W (under 500mA), that's a fairly small supply. I'll leave it for now. Maybe get your thoughts? And I need to consider the AC side. the12volt might not allow that sort of design for legal or safety reasons. BTW - you're on the right track with the cap, but that was only 10V rated (BANG!!). For 12V DC you could use a 16V rated cap, though I'd prefer 25V - probably because I'm so used to working with automotive 12V which means 14.4V and high temperatures, but often 15V and higher - so 25V is the normal "minimum" cap voltage rating for 12V auto systems.

I think I understood your "insane logic." If I understand you correctly, a dimming transformer is not a good way to go and I should instead go with a plugpack. I looked into using a plugpack a little bit prior to my posting on here, but I wasn't sure about them. I've read your comments several times and although I think I understand most of it, I'm going beyond my knowledge/comfort level with this stuff. You're idea of a plugpack got me thinking of going with a more "premade" way. Now if I go this route, I'd buy one of these LED strips and cut it to size. I'd then fasten this power supply to the inside of the record player and use this for the dimmer. What do you think of this setup? Its a little more than I anticipated on spending, but it sure would be less of a headache for me. I appreciate you help, but like I said, I'm going beyond my knowledge with this stuff. Although if you think I'm over complicating things in my head and just taking the easy way out, feel free to reach through the internet, slap me across the face and set me straight. Sometimes I over complicate things in my head and need to be set straight.

I don't know why but the link in the above post to the power supply isn't working for me. If its not working for you either, here's the URL: http://www.amazon.com/Ledwholesalers-Power-Suppply-Driver-Transformer/dp/B0034GUEY4/ref=pd_bxgy_hi_img_z

How much current capacity on the 2.6 volt output? Most LED's will illuminate very brightly with 2.6 volts.

I don't remember what reading I picked up when I measured current. I'll have to look when I get home. However, I'm pretty sure I want to bypass the existing wiring anyway. Like I said, there's 2.6V running through there, but its not enough to move the turntable or the arm. If I remove the turntable, then and only then will the motor work. Its like there's enough power to move the motor freely, but not enough to move the turntable. I inherited this record player from my brother, and I think he may have tried to fix it at some point. So my worry is he messed something up while trying to fix it.

Without the platter attached to the motor, and the motor turning, what is the voltage across the motor? Do you need the motor to turn in your project? You will not be able to get a current output capacity with only a meter.

The voltage is roughly 2.6V without the platter. I'm not sure what it is with the platter, or even if it is different, because I had to remove the platter in order to check the voltage.