Alternating current (AC) is the most efficient way to supply electricity. However, most electronic devices need direct current (DC) to function. For this reason, AC-DC converters, from alternating to direct, can be part of the devices themselves or of their power cables. If you have built a device that you want to power from the power outlet, you need to add such a converter.
Steps
Step 1. Determine what the AC input voltage is
In North America and parts of Central and South America, the AC voltage at most outlets is 110 - 120 volts at 60 hertz. In Europe, Asia, Australia and much of the Middle East and Africa, it is 230 - 240 volts at 50 hertz. The standard in other countries may further differ.
Step 2. Find the voltage and amperage needed to power the components of the electronic device
Check the manufacturer's instructions if necessary. An amperage or a voltage that is too high will destroy the components, however, if it is too low, it will not allow the device to function properly. Most work in a safe range around a central value, so the input power can vary a bit.
Step 3. Use a reducer to turn down a high to low voltage AC output
Current enters the primary coil of the reducer and induces a current in the secondary coil, which has fewer turns, resulting in a lower voltage. Little power is lost in this process, because the amperage increases in relation to the decrease in voltage.
Step 4. Run low voltage AC through a rectifier
A rectifier is usually made up of four diodes arranged in a diamond shape: it is called a "bridge". A diode only allows current to flow in one direction. The diamond configuration allows two diodes to pass the positive half-waves of the current, while the other two let the negative half pass. The output from both groups is a current that rises from 0 volts to the maximum positive voltage.
Step 5. Add a large electrolytic capacitor to rectify the voltage
A capacitor stores an electrical charge for a short time and then releases it slowly. The inlet of the rectifier resembles a sequence of humps, while its outlet is an almost constant voltage, with ripples.
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For devices that only need low current, you can make a rectifier with a resistor and a zener diode, which is designed to break down the voltage when a certain peak is reached, allowing current to pass through it. The resistance limits the current.
Convert AC to DC Step 5Bullet1
Step 6. Pass the rectifier output through a regulator
This smooths out the ripples and creates a very stable current that will operate in the electronic device without damaging it. Regulators are integrated circuits and can have both fixed and variable output voltages.
Although regulators include protection against excessive heat and current, yours may need a heatsink to keep from getting too hot
Advice
- Alternating current includes positive and negative voltages that rise and fall as in a smooth sine wave (sine wave). They can carry energy faster and farther without wasting energy.
- If you don't want to build your own AC - DC converter, you can always buy one.
