1. TL084ID Substitution Conclusion The TL084ID can be substituted with caution, but three key differences must be noted: First, its lower gain-bandwidth product (3 MHz vs. 4 MHz) may reduce small-signal gain at higher frequencies. Second, the quiescent current is significantly lower (1.4 mA vs. 7.2 mA), which benefits power consumption but may affect output drive capability and dynamic performance. Third, the supply voltage range is narrower (10–30 V vs. 7–36 V), limiting flexibility in low-voltage applications. Substitution is acceptable if the circuit operates above 10 V, does not demand high bandwidth, and prioritizes low power consumption; otherwise, actual performance should be verified.