The output is converted to DC by diodes (black component, upper right), and filtered by capacitors (cylinders), to produce the 20 volt output (wires at bottom). The pulses create a changing magnetic field in the flyback transformer (large blue box), generating a high-current, low-voltage output. The AC power comes in the red wires at the top and is converted to high-voltage DC (170V or 340V, depending on if you're in the US or Europe).Ī transistor (black component on left) chops the power into high-frequency pulses. I've written in detail before about how chargers work, but I'll give a quick explanation here. The genuine charger includes more filtering, power factor correction (left), and a powerful microcontroller (board in upper right). The cheap MacBook charger (left) omits most of the components found in a genuine Apple charger (right). The Apple charger also includes power factor correction, making the charger more efficient. Many of these components filter the power to provide higher-quality power to your laptop.
On the other hand, the genuine Apple charger (right) is crammed full of components. Since this processor increases the cost of the charger, knockoff chargers omit it, even though this makes the charger more dangerous.Īs the photos below show, the cheap charger (left) omits as much as possible. (more powerful than the microprocessor in the original Macintosh by some measures). To manage this, the genuine charger includes a powerful microcontroller Until it is properly connected ( details), it outputs a tiny amount of power (0.6 volts at 100♚) that can't produce a spark. On the other hand, the genuine charger doesn't power up until it has been securely connected to the laptop for a full second. The fake charger constantly outputs 20 volts, so if any metal shorts the connector, it produces a big spark with all its 85 watts of power. Why does a fake charger produce sparks, while a genuine one doesn't? Unlike most cheap chargers, this one doesn't claim to be an Apple charger, but just a "Replacement AC Adapter".