Logic Circuit

In computer engineering, logic circuit or logic family may refer to one of two related concepts.  A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compatible logic levels and power supply characteristics within a family. Many logic families were produced as individual components, each containing one or a few related basic logical functions, which could be used as "building-blocks" to create systems  or as so-called "glue" to interconnect more complex integrated circuits.

The list of packaged building-block logic families can be divided into categories, listed here in roughly chronological order of introduction, along with their usual abbreviations:

1. Resistor–transistor logic (RTL)
   1.1 Direct-coupled transistor logic (DCTL)
   1.2 Resistor–capacitor–transistor logic (RCTL)

2. Diode–transistor logic (DTL)
   2.1 Complemented transistor diode logic (CTDL)
   2.2 High-threshold logic (HTL)

3. Emitter-coupled logic (ECL)
   3.1 Positive emitter-coupled logic (PECL)
   3.2 Low-voltage positive emitter-coupled logic (LVPECL)
   3.3 Complementary transistor micrologic (CTuL)

4. Gunning transceiver logic (GTL)

5. Transistor–transistor logic (TTL)

6. P-type metal–oxide–semiconductor logic (PMOS)

7. N-type metal–oxide–semiconductor logic (NMOS)
   7.1 Depletion-load NMOS logic
   7.2 High-density nMOS (HMOS)

8. Complementary metal–oxide–semiconductor logic  (CMOS)

9. Bipolar complementary metal–oxide–semiconductor logic (BiCMOS)

10. Integrated injection logic (I²L)