Transistor-transistor logic (TTL) was first developed in 1965 using only transistors to perform logic operations. TTL integrated circuits were improved over the years and are still used today as "glue logic" to connect more complex digital devices. A basic TTL NAND gate uses transistors at the input where both low inputs forward bias the bases, resulting in a high output. The totem-pole output stage arrangement stacks three output components - a transistor, another transistor, and a diode - so that only one conducts at a time.
Transistor-transistor logic (TTL) was first developed in 1965 using only transistors to perform logic operations. TTL integrated circuits were improved over the years and are still used today as "glue logic" to connect more complex digital devices. A basic TTL NAND gate uses transistors at the input where both low inputs forward bias the bases, resulting in a high output. The totem-pole output stage arrangement stacks three output components - a transistor, another transistor, and a diode - so that only one conducts at a time.