What is an APC in electronics?

In electronics, APC has several meanings, and the right one depends on the field. These are the four most common.

1. American Power Conversion

APC is a brand of power protection equipment, owned by Schneider Electric. It makes UPS battery backups, surge protectors, PDUs and rack equipment. This is the most common meaning when you shop for computer or network gear.

2. Angled Physical Contact

In fiber optics, APC describes a connector whose end face is polished at an 8 degree angle. The angle sends reflected light into the cladding and not back to the source, which lowers back reflection. APC connectors are usually green. They are common in FTTH, PON and CATV networks. They should not be mixed with blue UPC connectors, because the mismatch can damage the end faces and cause signal loss.

3. Automatic Power Control

In laser diode and optical transmitter circuits, an APC loop keeps the light output steady by adjusting the drive current using a monitor photodiode.

4. Advanced Process Control

In semiconductor and industrial manufacturing, APC refers to software and control methods that adjust process settings to keep production within specification.

How to tell which one you need

• Shopping for battery backup or surge protection: American Power Conversion.
• Buying fiber patch cords or connectors: Angled Physical Contact.
• Working on laser or optical driver design: Automatic Power Control.
• Working in a fab or factory: Advanced Process Control.

If you see green fiber connectors labeled APC, they are angled physical contact connectors.