Transistor resistor logic circuit analysis

Transistor Resistor Locic (TRL) merits consideration as a form of semiconductor logical circuitry for data-processing systems as a consequence of its inherent simplicity, reliability and economy. The basic TRL building block and flip-flop are shown. The building block is seen to consist of a resistor OR gate followed by an inverting transistor amplifier. Any combinational logic function can be implemented using this block alone. The flip-flop consists of two building blocks connected back to back. The TRL circuit has found application in several relatively slow-speed digital systems. It is the purpose of this paper to present the results of a new look at TRL using several new high-speed, high-gain transistors. It is shown that the excellent properties of these transistors can be effectively exploited with TRL circuits operating economically and reliably at the moderately high speeds required in many digital systems. The analysis which follows primarily involves current relationships, since the operation of TRL circuits involves the switching of nearly constant current sources.