Logic families are classified into two catefories. They are

1. Bipolar logic families

2. Unipolar logic families

Bipolar logic families :

The main elements of a bipolar IC are diodes and transistors. In this classification they are further divided into two types based on BJT operating mode. They are  :

1. Saturated mode

2. Non-saturated mode

In saturated logic, the transistors are driven to saturation mode, the saturated bipolar logic families are:

1. Resustor-Transistor Logic(RTL)

2.Diode Tranmsistor Logic (DTL)

3.Direct Coupled Tranmsistor Logic (DCTL)

4.High Tranmsistor Logic (HTL)

5.Tranmsistor Tranmsistor Logic (TTL)

6.Integrated Injection Logic(IIL)

The non saturated bipolar logic families are :

1.Schottky TTL

2.Emitter coupled logic (ECL)

Unipolar logic families :

MOS devices are unipolar devices and only MOSFETs are employed in these MOS logic circuits. The MOS logic families are

1.PMOS

2.NMOS

3.CMOS