Point of reference - an indicator that orients you generally; "it is used as a reference for comparing the heating and the electrical energy involved"
You have several electrical units listed there:
a). C often used to represent a Capacitance.
b). 'A' often represents 'Ampere', the unit of Current.
c). 'R' often used to represent a Resistance.
d). 'E' often used to represent a Voltage (Electromotive Force).
Not to mention ' A. C ', a whimsical offering,
reminiscent of 'Alternating Current'.
The answer is Fuse. Circuit breakers and fuses are generally known as "Overload Protection Devices. The difference between a fuse and a circuit breaker is that a fuse is a one time circuit element while a circuit breaker is a multiple use device. If you were designing a circuit for a reading lamp, a fuse would do. Since almost all household installed a circuit breaker for outlets, etc,
Precisely around 1,800 miles below.
