Sample & Hold Circuits are ICs (integrated circuits) that sample the voltage of ani input analog signal that is continuous and retain the value at a consistent level for an amount of time set by the user. This generation of the sample of the input signal is called sampling time
Sample & hold circuits are primarily used in linear systems to compare voltage generated via a DAC (digital-to-analog converter). The circuit tests values until the voltage is equal. Each value is then sampled and held utilising a sample clock.
Most commonly in ADCs (analog-to-digital converters) to remove variations in the input signal. They are utilised in musical instruments such as synthesizers to impart effects on randomly to played notes.
Sample and hold circuits are also used in other applications such as;