In electronics, a sample and hold (S/H, also "follow-and-hold") circuit is an analog device that samples (captures, grabs) the voltage of a continuously varying analog signal and holds (locks, freezes) its value at a constant level for a specified minimum period of time. Sample and hold circuits and related peak detectors are the elementary analog memory devices. They are typically used in analog-to-digital converters to eliminate variations in input signal that can corrupt the conversion process.
A typical sample and hold circuit stores electric charge in a capacitor and contains at least one FET (field effect transistor) switch and at least one operational amplifier. To sample the input signal the switch connects the capacitor to the output of a buffer amplifier. The buffer amplifier charges or discharges the capacitor so that the voltage across the capacitor is practically equal, or proportional to, input voltage. In hold mode the switch disconnects the capacitor from the buffer. The capacitor is invariably discharged by its own leakage currents and useful load currents, which makes the circuit inherently volatile, but the loss of voltage (voltage drop) within a specified hold time remains within an acceptable error margin.
Sample and Hold is a remix album from Simian Mobile Disco. It was released July 28, 2008 on Wichita Recordings. The track listing resembles that of Attack Decay Sustain Release with the addition of a remix of "Clock", a track from Clock EP released in March 2008.
Each track of the album had been hand picked by James Shaw and James Ford, selected from remixes that have been made by DJs the duo encountered during their worldwide travels.