Emitter-coupled logic
（重定向自Current steering logic）
![Motorola ECL 10,000 basic gate circuit diagram[1]](/Images/godic/202501/07/ECL.svg4929.png")
![Yourke's current switch, c. 1955.[9]](/Images/godic/202501/07/CurrentSwitchLogic.svg4929.png")
![The picture represents a typical ECL circuit diagram based on Motorola's MECL. In this schematic, transistor T5′ represents the output transistor of a previous ECL gate that provides a logic signal to input transistor T1 of an OR/NOR gate whose other input is at T2 and has outputs Y and Y. Additional pictures illustrate the circuit operation by visualizing the voltage relief and current topology at low input voltage (logical](/Images/godic/202501/07/ECL_structure_10004929.jpg")
In electronics, emitter-coupled logic (ECL) is a high-speed integrated circuit bipolar transistor logic family. ECL uses an overdriven BJT differential amplifier with single-ended input and limited emitter current to avoid the saturated (fully on) region of operation and its slow turn-off behavior. As the current is steered between two legs of an emitter-coupled pair, ECL is sometimes called current-steering logic (CSL), current-mode logic (CML) or current-switch emitter-follower (CSEF) logic.