TTL-Transistor to Transistor Logic

Transistor-transistor logic, It is a common type of digital circuit in which the output is derived from two transistors. The first semiconductors using TTL were developed by Texas Instruments in 1965. The term is commonly used to describe any system based on digital circuitry, as in TTL monitor.

With the rapid development of integrated circuits (ICs), new problems were encountered and new solutions were developed. One of the problems with DTL circuits was that it takes as much room on the IC chip to construct a diode as it does to construct a transistor. Since "real estate" is exceedingly important in ICs, it was desirable to find a way to avoid requiring large numbers of input diodes.