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.
Legal studies is a subject that can be learned and used regardless of whether you plan to practice law. There are other career choices available to people with degrees in legal studies. It helps to have background knowledge in business, finances, or other subjects relevant to the career of your choice, as well.