74LS138 is a member from ‘74xx’family of TTL logic gates. The chip is designed for decoding or de-multiplexing applications and comes with 3 inputs to 8 output setup.
LM339 is a voltage comparator IC from LMx39x series and is manufactured by many industries. The devices consist of four independent voltage comparators that are designed to operate from a single power supply.
DAC7715 is a ‘Digital to Analog Converter’ chip designed by Texas Instruments and is available in SOIC-16 package only. The chip takes in 12 bit serial data and provides analog output at any one of selectable four output channels.
HX711 is an ADC chip with preamplifier included. The chip is specifically designed for weight scales applications. The load cells which usually measure weight provide voltage outputs in millivolts.