(1 + c)/(r + e + c). The money multiplier (also called the credit multiplier or the deposit multiplier) is a measure of the extent to which the creation of money in the banking system causes the growth in the money supply to exceed growth in the monetary base.
A buzzing light switch could mean the fixture is wearing out, causing an arc of electricity behind the wall plate. If this is the case, the potential for an electrical fire may exist.
It was a simple electric circuit containing a battery, a switch, and an electric motor standing on a large cardboard box. When a caller pressed the switch, the battery fed power to the motor and made it spin around with a buzzing noise (a bit like the vibrating alert on a cellphone or pager).