Analog Helpers on Digital Logic Notebook

Comparators

Mon, 01 Jan 0001 00:00:00 +0000

Comparators#

A comparator is the doorway from the analog world into the digital one. It looks at two analog voltages and produces a single logic bit: high if the positive input is above the negative input, low otherwise. Every threshold decision a digital system makes about a continuous signal — is the battery low, has the sensor crossed a level, did the waveform cross zero — starts at a comparator.

Analog Switches

Mon, 01 Jan 0001 00:00:00 +0000

Analog Switches#

An analog switch lets a digital signal turn an analog one on and off. Where a logic gate can only handle clean highs and lows, an analog switch passes whatever voltage sits on it — an audio signal, a sensor output, a reference — while a logic-level control decides whether the path is open or closed. It is the fundamental primitive for routing analog signals under digital control.

Sample & Hold

Mon, 01 Jan 0001 00:00:00 +0000

Sample & Hold#

A sample-and-hold captures an analog voltage at a chosen instant and holds it steady long enough to be measured. It exists because measurement takes time: an analog-to-digital converter needs its input to stay constant while it works out the digital value, and a signal that moves during the conversion produces a wrong reading. Sample-and-hold freezes the signal at a defined moment so the converter has something still to look at.

Op-Amps (Briefly)

Mon, 01 Jan 0001 00:00:00 +0000

Op-Amps (Briefly)#

The operational amplifier is the general-purpose gain block of analog electronics, and it earns a place in a digital notebook only for what it does at the boundary: conditioning a real-world signal so the digital side can use it. This page stays deliberately brief — the full treatment of op-amps belongs to the EE Notebook’s analog sections.

What It Is#

An op-amp is a high-gain differential amplifier. On its own that open-loop gain is unusably large, but wrapped in feedback it becomes precise and versatile: amplify, attenuate, buffer, filter, sum, or offset a signal, with the behavior set by a handful of external resistors and capacitors. It is the analog equivalent of a Swiss-army knife, and a comparator is essentially the same device run without feedback so its output swings fully to the rails.