• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

24 Vac - 12Vdc Rectifier

Status
Not open for further replies.

theunfrailhale

New Member
Hello and thanks for reading this,

I am a technician in a sheet metal shop and I endup doing a lot of machine repairs. We have a machine that cuts 10 foot pieces of sheet metal, and there is a bar with standard incandescent bulbs to help you line up your cut. These Bulbs constantly burn out and blow fuses. The Bar they are mounted on moves with the cutting beam, and I think that the often jarring motion is taking its toll on the lights.

My solution is to install LED lighting which is more durable and brighter than the existing light strips. there are 15 lights spaced apx 8 inches apart in small recesses in the bar.

the current output voltage is 24 v ac.

I have done a little reading on google and found some very useful articles, but this being one of my first "electronics" ventures, i am hesitant, because i dont really know what im doing :D

Building a Power Supply - Electronics in Meccano

this is an article that i found very useful, and their package rectifier board (figure 5 at the bottom of the page) project converts 7-35 v ac into an output of 5Vdc

although i know it isnt much to assemble led circuits I may opt to go with some modules i found that seem to be useable and simple, unless i am otherwise convinced.

LBM Dimensions (mm)

these modules need an input of 10- 14.5 V DC, so the output of the afore mentioned is going to be insufficient.

I am not sure what determines the output voltage in their circuit. I know the rectifier will reduce voltage by something like 0.4 v according to the articles following pages. and the capacitor will be a smoothing agent, so it seems to me that the 7805 regulator is where its at?

Also the existing lights as may be assumed are connected in parallel which is how i plan to configure the replacements. i know that parallel resistors reduce the overall resistance of a circuit, but im thinking that it increases the amperage, so what do I need to account for to prevent that?

Am I missing anything else???

i am telling you what i THINK i understand, so whatever is misunderstood, please correct me...

thanks again for the read, and the advice.
Dave.

PS, let me know if you need custom project boxes out of sheetmetal?:p
 

mxitman

New Member
I had built a simple 24VAC to 12VDC converter a few years back, I got the schematic from this circuit. http://www.reconnsworld.com/power/12vpowersupply.gif or Schematics Depot (tm) - 12 volt power supply

I of course used only a 24 VAC power supply from a HVAC transformer for this circuit. I built it for my brother who got a free Mitsubishi AC unit, but the control voltage used 12VDC instead of 24VAC so instead of changing everything I made this simple circuit installed in a small plastic box with 2 wires coming out each end, 24vac power in and 12vdc power out. whenever there was a call for cooling, the tsat would send the 24vac to the outdoor unit, hit my circuit and was now 12vdc so it could run the unit. Still working for the last 4-5 years. I omitted the led light and resistor for it.

That should work for you!
 

Attachments

Last edited:

blueroomelectronics

Well-Known Member
I used to love Meccano, I've still got a large box of almost perfect kits from the 1970s including the old M5 motor. Hmm perhaps eBay is calling.
 

theunfrailhale

New Member
thanks for the input, I appreciate the schematics and doesn't look much different from what i was excpecting...

Am i correct in assuming that since I already have a 24 VAC line, i dont need to include the transformer?

as far as buying components goes, if i took this to radioshack, or frys electornics, the component numbers (BR1 4A, U1 7812) are unique and would be simple to acquire?
 

Janis1279

Member
Am i correct in assuming that since I already have a 24 VAC line, i dont need to include the transformer?

as far as buying components goes, if i took this to radioshack, or frys electornics, the component numbers (BR1 4A, U1 7812) are unique and would be simple to acquire?
You dont need to include the transformer if
Usecondary(of Yours 24VAC transformer) * 1.44(voltage multiplier in full bridge + 3300uF capacitor schematic) <= 35V (Umax input voltage for 7812)
component number for U1 7812 is unique , small differences for every manufacturer.
From data sheet : With adequate heatsinking it can deliver output currents in excess of 1.0 A.
But BR1 4A , I thinks is max output current equal 4Amps for this bridge rectifier.
 

Attachments

tcmtech

Banned
Most Helpful Member
Check with Digikey or one of the other electronics components dealers. They carry loads of ready built 24VAC LED replacement lights that are a direct replacement for most standard incandescent lower voltage bulbs. Just match the base style and voltage of what bulb you have and pick out a color that you think would work best.
No power supply design required!
 
Status
Not open for further replies.

EE World Online Articles

Loading
Top