S-60-12 Power Supply Circuit Diagram [480p 2026]

“This capacitor holds the raw power,” Manish said. “But it’s also the most dangerous. It can shock you hours after unplugging.” Now came the magic. The high-voltage DC must be chopped into high-frequency pulses. The switching transistor —a MOSFET, usually a 2SK3878 or 5N60C—acts like a rapid switch, turning on and off tens of thousands of times per second.

The MOSFET’s source connects to a (a low-ohm, high-wattage resistor like 0.33Ω). This resistor tells the UC3842: “If too much current flows, shut down immediately.” It’s the overload protection. s-60-12 power supply circuit diagram

That wild, bumpy DC needs smoothing. And here stood the giant: the (C5, usually 100-150µF, 200V for 110V regions; or 68-82µF, 400V for universal input). On the S-60-12’s board, Manish found a chunky 100µF/400V capacitor. It stores energy between peaks, creating a flat(ish) high-voltage DC bus of about 170V (for 120V AC) or 340V (for 230V AC). “This capacitor holds the raw power,” Manish said

On his cluttered workbench lay a sad, dusty aluminum box. It was an —a 60-watt, 12-volt DC switching power supply. Its once-proud metal casing was dented, its fan grille clogged with years of sawdust. The label read: Input: 100-240V AC, Output: +12V @ 5A . Someone had tossed it because it “smelled like smoke.” The high-voltage DC must be chopped into high-frequency

The UC3842 needs a startup voltage. A few high-value resistors (two 150kΩ in series) trickle-charge a small capacitor (C6, 47µF/50V) until the chip wakes up. Once awake, the chip sends square waves to the MOSFET’s gate via a small resistor (e.g., 22Ω) and a fast diode.

The green LED on the output terminal glowed. The fan hummed. His oscilloscope showed a perfect 12.00V square wave under a 2A load.

He connected an old LED strip. It blazed to life.