Doorbells operate on very low voltage. Older models typically require just 8 to 20 volts of electricity -- most often 16 volts -- while newer models take 24 volts of electricity. Newer models have higher voltage output to accommodate longer runs of wire in larger homes.
Management is studied at colleges and universities; some important degrees in management are the Bachelor of Commerce (B.Com.) and Master of Business Administration (M.B.A.) and, for the public sector, the Master of Public Administration (MPA) degree.
A manager is a person responsible for pulling people and a project together -- and a management degree is your ticket to becoming that person. A business degree in management will greatly enhance your career opportunities.