A system for generating an electronic puzzle for a user. The current flowing to the base of a bipolar transistor that forms each reference amplifier depending on an input power level is detected, amplified, and supplied as base current of the transistor of the corresponding amplifier. The gate electrodes or the sourcedrain electrode pairs at the boundary region defined by both the first and second masks are divided into a first portion patterned by the first mask and a second portion patterned by the second mask.