How EXACTLY does a voltage regulator/stabulizer work?

Answer 1

To tell you EXACTLY, I'd need to know what kind it is (AC or DC). A even then then there are a couple of types.


But the principal principal of all of them is:

It knows what voltage it's putting out.
It knows what it's supposed to put out.
It will constantly make adjustments to itself to achieve a stable (consistent, accurate, etc) voltage based on the first two.

They usually work via a feedback mechanism.
Say that you are told to sing something at an exact volume so that it's heard in the cheap seats, but doesn't deafen people in the front row.
(Obviously this is not going to be a rock concert).

If you don't have a volume meter built into you, you'll need help.
So you'll need someone up in the nose bleed section to tell you when he can hear you.
He listens and you start singing until he waves a flag to let you know you're singing loud enough.
Unfortunately, there's a particularly vicious matron standing center front row (she's almost in the orchestra pit, but unfortunately not as close as you'd like).

So, anyway, after the flag wave, you starting singing more, and the guy up high says it's great (well, you think that's what he saying - but that's why he has a flag). In any case, he's still waving it.
The person in the front row has a whistle and starts to blow it and then says that you are too loud.

You sing a little quieter and the person in front says perfect, but the man in the top row lets his flag down, so you know that now he can't hear you (and he was the only one who liked your singing in the first place).

So you increase your voice and the lady says it's too loud, but the guy was just raising the flag up again.
You've got to find the exact volume you need from types of feedback.
Now, if this were voltage instead of volume, you'd have a feedback loop or circuit.


Voltage can be regulated by: resistors, zener diodes, transistors, integrated circuits, mechanically by a servo mechanism, relays, resistors, transformers (resonant or tapped), and capacitors.
Or, more than one and perhaps several of the above
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In a car battery charger (one of the more pricier one that will change from charge more to "trickle" mode without manual
intervention) for example:

You need to provide more than 12volts to recharge a 12 volt battery. Usually around 13.6-13.8 volts is used.

The battery will draw more amperage from the battery charger initially, but will require less and less as the battery becomes charged

Once it is charged, it draws 0 amps, and the battery charger cuts back down to 12 volts so it doesn't fry the battery and a very small amperage. It may also drop the voltage down as the current draw becomes less, but that slows the charging completion and increases the time required.

Answer 2

DC voltage regulation is done by a Zener Diode. This is a diode that conducts at a specific voltage.

Say you need 12.0 volts regulated at 300 mA and you have 15.0 volt supply. If you used a simple 10 Ohm resistor ([15-12]/0.3)you could drop the voltage down, but his is unregulated meaning that while the device was drawing current the voltage across would be 12.0 Volts, but as soon as you turned off the device, the voltage would jump to 15.0 volts. If you put a 12.0V 5W zener diode in parallel with the device, it would conduct whenever the voltage was above 12.0V, and keep the voltage regulated to 12.0V regardless of the load. You need to be careful in selecting the value of the zenner. In this case the zener must be able to handle 3.6 Watts (12 x 0.3). You can use transistors to regulate higher currents, but the zener will still be the heart of the regulator.

There are pre-made voltage regulators for DC, such as the 78xx family. A 7812 is a positive 12 volt 1A regulator in a simple 3 pin TO-220 package.

AC regulation is a bit more complex. Ferro-Resonant is the technology I'm most familiar with. It uses a transformer/capacitor setup that resonates at the power line frequency (60 Hz in my case). The voltage can vary considerable at the input, but the output voltage will stay closer to the design output voltage. One problem with this approach is the output will not be a perfect sine wave.

Newer AC to DC switcher power supplies (Like your computer power supply) actually take the AC input, and convert it to DC with diodes. Then pulse the DC up to a higher frequency and use a small transformer to increase or decrease the voltage. Another set of diodes brings it back to pulsating DC, then a capacitor/inductor setup is used to filter the DC. Regulation is done with a feedback loop from the secondary to the primary. The pulsed DC on the input side of the transformer is increased or decreased depending on the power requirement.

Answer 3

Well if you want a Universal AC adapter is what comes regulated or not. The best ones are regulated because if they aren't and you want to use it to give out for example 12 volts then if it's not regulated it will give out like either 15 or 8 volts and not what you need. But a regulated one which is a little bit more money that is regulated actually gives out the correct amount you wanted. So basicaly a voltage regulator/stablizer stablizes and makes sure a correct amount of power is coming out, you find those a lot on cords for laptops, they are the big black boxes on the cords, they make sure the correct amount of power goes to the computer so that the computer isn't ruined by incorrect voltage power in other countries since other countries are different voltages. Well i hope that explanis what you wanted to know.

Answer 4

Its complicated. Buy some and play with them to get a feel for it.

Look at a schematic for a simple power supply and make one.

You need a "bridge" to clip the ac to dc, then a few large caps, then a voltage reg, probably with heat sink, maybe a switch and a fuse too.

Answer 5

transforming DC to AC
V=IR=I'R"