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A programmable-gain amplifier -LRB- PGA -RRB- is an electronic amplifier -LRB- typically an operational amplifier -RRB- whose gain can be controlled by external digital or analog signals .. electronic amplifier. electronic amplifier. operational amplifier. operational amplifier. gain. Gain ( electronics ). digital. Digital signal ( electronics ). analog. Analog signal. The gain can be set from less than 1V / V to over 100V / V .. gain. Gain ( electronics ). Examples for the external digital signals can be SPI , I ² C while the latest PGAs can also be programmed for offset voltage trimming , as well as active output filters .. digital. Digital signal ( electronics ). SPI. Serial Peripheral Interface Bus. Popular applications for these products are motor control , signal and sensor conditioning .