The A20112 (often referred to as R2A20112 or R2A20112ASP) is an integrated circuit (IC) primarily used as a Power Factor Correction (PFC) controller in high-efficiency switching power supplies (SMPS) . Overview of R2A20112
, which works by dropping the voltage to the screens of the power tubes (Pentode/Triode switching). Common Components in A20112 Supplies Component Type Common Value/Part Power Tubes 2x 6V6 or EL84 Main power section 5AR4 or Diodes Converts AC to DC Screen and grid resistors Capacitors 22uF - 50uF (450V) Filtering Ripple Troubleshooting Tip a20112 power supply schematic
: Uses a series of high-voltage electrolytic capacitors (e.g., 22uF to 47uF rated at 450V+) and often a choke or large power resistors to smooth the DC voltage. Switching Options : Some versions include a 7W/14W power switch The A20112 (often referred to as R2A20112 or
When a 20112 stops working, techs often look for these common "characters" in the story of the circuit: R25 fixed, increase R24: R24 = (Vout/2