S-60-12 Power Supply — Circuit Diagram
“You see?” he told his young apprentice. “Every component tells a story. The S-60-12 is not just a power supply. It’s a translation—from the raw, chaotic energy of the grid to the peaceful, precise language of electronics.”
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.
A small variable resistor (VR1, a 1kΩ trimpot) lets you adjust the output from ~10V to 14V. But the real hero is the programmable shunt regulator and an optocoupler (PC817). s-60-12 power supply circuit diagram
In a cramped, sun-drenched workshop on the edge of the city, old Manish had a rule: “Never throw away a power supply. Its heart may still beat.”
“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. “You see
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.
He connected an old LED strip. It blazed to life. It’s a translation—from the raw, chaotic energy of
Who commands this switch? A tiny 8-pin chip: the . In most S-60-12 units, it’s a UC3842 or KA3842 (a current-mode PWM controller). Manish found the chip near the optocoupler.