How many logic levels does a TTL circuit operate with?

A TTL (Transistor-Transistor Logic) circuit operates with two logic levels, corresponding to the binary states of 0 and 1. In TTL, these levels are defined by certain voltage ranges; typically, a logic low (0) is represented by a voltage between 0 to 0.8 volts, while a logic high (1) is represented by a voltage between 2 to 5 volts. This binary representation allows TTL circuits to perform logical operations, making them essential in digital circuits.

While there are other types of circuits that may use more than two logic levels or states, TTL specifically is designed for binary operation, focusing on simplicity and high-speed switching between these two distinct logic levels.