Resistor-transistor logic

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Resistor-transistor logic (RTL) is a class of digital circuits built from bipolar junction transistors (BJT), and resistors; it is the earliest transistorized digital logic used. It is called resistor-transistor logic because the logic gating function (e.g. AND) is performed by a resistor network and the amplifying function is performed by a transistor (contrast this with DTL and TTL).

It's main limitation was its limited Fan-In, 3 inputs being the limit for many circuit designs, before it completely lost usable noise immunity. A detailed treatment with applications is found in the RTL Cookbook by Donald Lancaster.

[edit] See also

• diode-transistor logic (DTL)
• transistor-transistor logic (TTL)
• emitter coupled logic (ECL)
• Integrated injection logic (I2L)