Buzz
Today, we’ll take a closer look at the transformer featured here.
MytourHave you ever counted how many power cubes are scattered around your home? Here’s what I discovered in mine:
- The answering machine
- The cordless phone
- The cell phone
- The ultrasonic anti-flea device (we own 4 dogs)
- The digital camera
- The nicad battery charger
- The video camera battery charger
- The bedroom digital clock
- The electric toothbrush
- The electric razor
- The electric screwdriver
- The electric drill
- Both units of the baby monitor
- The laptop computer
- The office phone
- The inkjet printer
- The computer speaker system
- The office tape recorder for note-taking
- The calculator charger
- The 9-volt battery adapter for the radio
- The RadioShack universal power cube
A total of 22! (Don’t forget, the baby monitor includes 2 units.) Each one is unique—varying in plug types, voltage ratings, and amperage.
Let’s dismantle one of these to uncover its internal components.
Under the cover
After removing the cover, here’s what you’ll discover inside.
MytourThis transformer was included with a rechargeable electric screwdriver. It’s designed to operate at 3 volts and 240 milliamps.
Inside, you’ll notice two windings. Transformers are designed to convert AC voltage from one level to another. In this instance, it reduces the standard 120-volt household current to just 3 volts. The primary winding on the left receives the 120-volt input. An iron core runs through the center and around the exterior of this winding. The AC current in the primary winding generates an alternating magnetic field within the iron, similar to an electromagnet. The secondary winding, which surrounds the same iron core, produces current through this magnetic field. The voltage in the secondary winding depends on the ratio of turns between the two windings. If both windings have the same number of turns, the voltages will match. However, if the secondary has half the turns of the primary, its voltage will be halved. In this transformer, the primary winding uses thin wire, while the secondary employs thicker wire. To achieve a 3-volt output, the primary winding must have 40 times more turns than the secondary.
Converting AC current into DC current
On the opposite side of the transformer, you’ll notice two diodes encased in rubber insulation.
MytourThe two diodes on this side, protected by rubber insulation, function as a rectifier, transforming AC current into DC current.
Most household transformer cubes generate low-voltage DC current (ranging from 3 to 12 volts and under 1 amp). DC current is essential because rechargeable batteries store it, most electronic devices operate on low-voltage DC, and small DC motors, which run directly on batteries, are the most cost-effective option.
However, the pressing question remains—why hasn’t anyone standardized these small power cubes?
