Sandeep,
We can equate HR departement with Production departement and administration department with Maintenance Department
I will explain to you.
Maintenance Department : They normally carry out breakdown maintenance of machines, preventive maintenance, etc. and ensure the machineries in the shop floor are in working condition. This is normal routines they do periodically.
Similarly an administrative department or personnel department, do the normal routines like, payroll processing, statutory complinace (like submitting periodical returns), time office functions, etc. These are monotonous and regular jobs.
Production Department: As you may know, in production job there is INPUT ----> PROCESS ----> OUTPUT. The raw materials are put into oneside of the system, processed in different machines (drilling, turning, thread cutting, machining, grinding, boring, etc.) then comes as an output after the quality check, to be delivered to customers, is it not?
Similarly, an HR department's product is nothing but an employee himself. HR department hires a person, inducts him, teaches him the system and procedures, puts him onto the job, mould him to requirements, finds streghts and weaknesses (by performance review system), provides him necessary training/ retraining, plans career development and finally makes him available to the organization / department as a competent person.
It is developing an ordinary individual to an extraordinary employee to be used by the organiation for its business.
Therefore the HR department is usually known as "HRD department" - Human Resource DEVELOPMENT Department.
Hope I have clarified your doubt.
V. Balaji