S-60-12 Power Supply Circuit Diagram May 2026
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).
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. s-60-12 power supply circuit diagram
“This is the etiquette section,” Manish chuckled. “The power supply says, ‘I will take your energy, but I won’t pollute the radio spectrum.’” Next came the bridge rectifier —a black, square, four-pin component (often a KBL406 or similar). It takes the 120V or 230V AC sine wave and flips the negative humps upward, creating a pulsating DC voltage. Manish scoped it: a bumpy 120Hz waveform (if in North America) or 100Hz (in Europe).
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.” A small variable resistor (VR1, a 1kΩ trimpot)
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).
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 fan hummed
“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.
