Operational Amplifier (Op-Amp)

An operational amplifier, or op-amp, is a high-gain DC amplifier with two inputs: a non-inverting input (+) and an inverting input (-). It amplifies the tiny voltage difference between those two inputs by a very large factor (often 100,000 or more). On its own that gain is too high to be useful, so op-amps are almost always wrapped in negative feedback that tames the gain into a precise, predictable response set by a few external resistors.

Where op-amps appear in mining hardware

Op-amps do the quiet analog work that keeps a power supply honest. As comparators, they trip protection circuits when a rail goes out of range. As buffers, they isolate a fragile reference voltage from a heavier load. As precision amplifiers, they scale the tiny millivolt drop across a current-sense shunt up to a usable level that an analog-to-digital converter can read. This is how a PSU or hashboard knows how much current each voltage domain is drawing.

Real-world limits

Practical op-amps are not ideal: they have input offset voltage, finite bandwidth, and a slew-rate limit, and their output cannot swing all the way to the supply rails unless they are a rail-to-rail design. For a repair technician, an op-amp in a monitoring or feedback loop is usually robust, but a damaged one can cause a power supply to misread current and either shut down prematurely or fail to protect itself. Confirming the supply rails and reference voltages around the op-amp is the practical first check.