Question

A transformer connected to a 120-V (rms) ac line is to supply 13,000 V (rms) for a neon sign. To reduce shock hazard, a fuse is to be inserted in the primary circuit; the fuse is to blow when the rms current in the secondary circuit exceeds 8.50 mA. What current rating should the fuse in the primary circuit have?

Answer 1

The current is 0.921 A.

Step-by-step explanation:

Given that,

Voltage = 120 V

Current = 13000

Current exceeds = 8.50 mA

We need to calculate the current rating

Using relation of current and voltage

`(I_(p))/(I_(s))=(V_(s))/(V_(p))`

`I_(s)=(I_(p)*V_(p))/(V_(s))`.....(I)

Where,
`I_(s)` = current in primary circuit

`I_(s)` = current in secondary circuit

`V_(s)` = voltage in primary circuit

`V_(s)` = voltage in primary circuit

Put the value into the formula

`I_(s)=(13000*8.50*10^(-3))/(120)`

`I_(s)=0.921\ A`

Hence, The current is 0.921 A.