The armature characteristic, also known as the regulation characteristic, refers to the relationship between the terminal voltage of a DC generator and the load current. It is an essential characteristic that describes the behavior of a generator under varying load conditions.

**Explanation:**

**Armature Characteristic:**
The armature characteristic is a graphical representation of the terminal voltage of a DC generator against the load current. It shows how the terminal voltage changes as the load current varies. The armature characteristic is typically obtained by conducting a load test on the generator and measuring the terminal voltage at different load currents.

**Regulation Characteristic:**
The regulation characteristic is another term used to describe the armature characteristic. The word "regulation" refers to the ability of a generator to maintain a constant voltage output under varying load conditions. The regulation characteristic indicates how well the generator can regulate its output voltage.

**Relation to Terminal Voltage and Load Current:**
The armature characteristic shows that as the load current increases, the terminal voltage of the generator decreases. This is due to the voltage drop across the armature resistance and reactance, as well as the voltage drop caused by the internal losses of the generator. The armature characteristic helps in determining the regulation of the generator.

**Importance of Armature Characteristic:**
The armature characteristic is important because it provides valuable information about the performance and stability of a generator. It helps in determining the regulation of the generator and its ability to maintain a constant voltage output. By analyzing the armature characteristic, one can assess the performance of a generator under different load conditions and make necessary adjustments or modifications to ensure optimal operation.

**Conclusion:**
In conclusion, the armature characteristic, also known as the regulation characteristic, is an important characteristic of a DC generator. It describes the relationship between the terminal voltage and load current of the generator and provides insights into the generator's performance and stability. By understanding the armature characteristic, one can assess the regulation of the generator and make necessary adjustments to ensure optimal operation.