The identifier typically refers to a surface-mount fuse PTC resettable fuse
Whether you are designing industrial controls, automotive electronics, or power supplies, understanding how to properly implement this PolySwitch is key to protecting your hardware from overcurrent events. Understanding the F4901 1.1A 24V PPTC f4901 1.1a 24v schematic
+-----------------+ | AC Input (L) | +--------+--------+ | F1 (Fuse 1.5A Slow) | +----+----+ | L1 (Common Mode Choke) +----+----+ | | C1 (X2) | | | +----+----+ | Bridge Rectifier (DB1) | +----+----+ | | C2 (100uF/400V) | +---+---+ | R2 (Startup Resistor - 150k)| +---+---+ | Primary Side IC (PWM Controller - Likely OB2263 or AP8012H) | +---+---+ +---------+ | Q1 (MOSFET - 4N60)|-----| T1 (Transformer) | +---+---+ +----+----+ | | R3 (Current Sense - 0.68 Ohm) | | | GND Secondary Winding | +---+---+ | D1 (Schottky Diode - SB3100)| +---+---+ | C3 (470uF/35V) | +---+---+ | R4 (Load Resistor - 1k)| +---+---+ | +---+---+ | U2 (Optocoupler - PC817)| +---+---+ | +---+---+ | U3 (Voltage Ref - TL431)| +---+---+ | R5 & R6 (Voltage Divider for 24V) | 24V DC Output (+) GND Secondary (-) The identifier typically refers to a surface-mount fuse