Looking for a 24V AC to 12V DC circuit 1A.

[shemo]

anybody knows a circuit that can convert 24VAC to 12VDC at 1A?

Is transformer the best solution in terms of power dissipation. I see some LM part but they require heatsink.

 

[goldsmith]

anybody knows a circuit that can convert 24VAC to 12VDC at 1A?

Is transformer the best solution in terms of power dissipation. I see some LM part but they require heatsink.

Hi Shemo
You have many ways for this purpose . if the wave shape isn't important for you , use a triac to control the phase angel and then average will be changed .
If the wave shape is important to you , one of the good solutions is transformer because ration of your in/out voltages are not high and it means your transformer will be small .

Best Wishes
Goldsmith

 

[memarian]

anybody knows a circuit that can convert 24VAC to 12VDC at 1A?

Is transformer the best solution in terms of power dissipation. I see some LM part but they require heatsink.

Hi,

There are many ways to do this.Easiest one is to use a diode bridge with capacitor and a linear regulator (like LM317) , but your power dissipation will be high and you will need a good & large heat-sink.

For this problem , you should use a switching regulator. First you should use a diode bridge and capacitor for changing 24V AC to unregulated 32~33V DC, and use a step down switching regulator like LM2576 after that, with around 80% efficiency, you may need a reasonable heatsink (depends on your actual load).

if you don't need a good load/line regulation (output voltage will change with your load) a transformer and a simple diode bridge will be enough.

Personally i will use LM2576.

Good Luck!

 

[goldsmith]

Hi again
Oops ! when i sent my former post above was too late it was 5:38 morning and i was still awake . so my eyes was seeing some sort of hallucinations ! ha ha .
In that moment of time i saw AC to AC converter to it's why i left that funny post . sorry for that . For that simple application 7812 is ok but it deals with a lot of dissipation . switching regulators are fine here as ''memarian'' mentioned above LM2576 is good too .
Good Luck

 

[BradtheRad]

A choke input filter acts differently from a common smoothing capacitor.

The smoothing capacitor will give you 32 or 33 VDC (with a light load).

The choke on the other hand gives you 20 VDC with some ripple.

To drop this to 12V with a linear regulator will dissipate several watts, requiring a heatsink.

 

[memarian]

A choke input filter acts differently from a common smoothing capacitor.

The smoothing capacitor will give you 32 or 33 VDC (with a light load).

The choke on the other hand gives you 20 VDC with some ripple.

To drop this to 12V with a linear regulator will dissipate several watts, requiring a heatsink.

The main problem with choke is when your load change output waveform also change , for example when you turn on the power supply (usually without any load or something like a 10 ma load for a LED) the choke is almost useless and acts like a short circuit.

 

[BradtheRad]

The main problem with choke is when your load change output waveform also change , for example when you turn on the power supply (usually without any load or something like a 10 ma load for a LED) the choke is almost useless and acts like a short circuit.

Yes, you are correct.

I have wondered if a magnetic amplifier could be of use in this kind of application. It has to do with altering AC current in an inductor, by sending a small DC current through a separate winding. It is not a well-known tactic, which suggests it is not easy to carry out, or perhaps has limited usefulness.