how to convert AC16V to DC12?

[Gr8_ViruZ]

Hi everyone, I've a device which says on the lable DC12V 0.6W, I want it to work on a output AC16V 1000mA power supply.

I've came out a thought, but don't know if it works.
for AC to DC, I can use 4 diodes and a filter cap to built a Bridge Rectifier to convert it to DC.

for it able to work on 16V

as the device says DC12V 06.W, so use ohm's law.
the current = 0.6W/12V=0.05A.
the resistance=12V/0.05A=240ohms

16V resistance=16V/0.05A=320ohms this is the resistance need to works on the 16V power. so the original 12V resistance is 240ohms and the 16V resistance is 320ohms. the difference is 80 ohms.

so what I means is add a 80ohms resistor in series to the device then it can be used on a 16V power supply???


I'm just beginner, have limited knowledge of electronics, maybe it completely wrong.

can anyone tell me will it works or not?
or anyone knows how to do? please tell me.

thanks in advance.

[audioguru]

Hi Gr8,
Welcome to our forum.
The transformer will produce an output of 16V RMS when it is loaded with 1A, its rating. It will be more with only a 50mA load, maybe as high as 20V or more. You will need to measure its output voltage with a 50mA load.

The rectifier's filter capacitor will charge to the peak voltage of the transformer's "16V" sine-wave, minus two rectifier diode voltage drops (1.6V total). The peak is the RMS voltage multiplied by 1.414 (the root of two).
So it could be as high as 26.7VDC (or more). You would need a 294 ohm resistor to drop that voltage down to 12V. It will dissipate 735mW, so a 2W resistor should be used, a 1W resistor would get very hot.
If the 50mA load current changes, the 12V will also change because it isn't regulated. The 12V will have ripple on it because the filter capacitor isn't perfect. A voltage regulator IC would eliminate the ripple and keep the voltage at 12V.

I hope you didn't try it with 80 ohms. the voltage would probably be 22.7V!

[Guest Alun]

Hi try this:

the 2200