A rail is a heavy conductor or printed circuit board trace that delivers a constant supply voltage, such as 5V, 3.3V, or ground, to multiple components in a system. Because they carry the aggregated current for many devices, rails must be designed with low impedance to prevent voltage drops. When an amplifier's output voltage hits the absolute maximum supply voltage, engineers say the signal is clipping against the rail.
Check the 5-volt rail with the oscilloscope to see if the switching regulator is injecting noise.
Also heard as
- power rail
- supply rail
Related terms
VCC
The positive power supply pin or voltage rail for an integrated circuit.
Headroom
The margin between the nominal operating level of a signal and the absolute maximum limit before clipping occurs.
Floating ground
A zero-volt reference point in a circuit that is intentionally isolated from earth ground.